European Nanoanalysis Symposium

Resume : Modern synchrotron radiation sources and even laboratory devices produces now really Big spectroscopic Data while studying transformations of the materials during the processes, such as charge-discharge of metal-ion batteries, catalytical reactions or fast photoinduced transformations. XANES region of X-ray absorption spectrum should be sensitive to the coordinates of all atoms in the local cluster around x-ray absorbing atom. In contrast to X-ray diffraction, a quantitative analysis of XANES spectra is rarely performed till now, especially in the case of Big Data sets obtained. The main reason is the larger amount of time required for theoretical analysis of a single XANES spectrum compared to X-ray diffractogram. For such time-consuming calculations, in the space of several structural parameters, we developed an interpolation approach based on machine learning algorithms [1]. Machine learning is an emerging tool for quantitative analysis of XANES spectra. The spectrum contains all information about local atomic structure around absorbing atom. The ultimate goal would be predicting xyz coordinates from a given spectrum in a similar way it is done in single crystal diffraction. Due to approximations in the theoretical description, limited energy range, experimental artefacts and correlations such approach is not established yet. Current applications of XANES to quantitative structural refinement using both local descent approaches and neural networks provide no estimations to the number of possible structural parameters that can be refined. It is not clear a priori how much structural parameters and with what precision can be refined. Our work determines the type of structural information, which can be extracted from a spectrum on the basis of descriptor concept. We provide a methodology to analyze the theoretical training set first before its application for refinement. As an additional result we show geometrical interpretation of the several descriptors of XANES. We have chosen Jupyter Notebook framework to be friendly for users and at the same time being available for remastering [2]. The analytical work is divided in two steps. First, the series of experimental spectra are analyzed statistically and decomposed into principal components. Second, pure spectral profiles, recovered by principal components, are fitted by theoretical interpolated spectra. We implemented different schemes of choice of nodes for approximation and learning algorithms including Gradient Boosting of Random Trees, Radial Basis Functions and Neural Networks. The fitting procedure can be performed both for a XANES spectrum or for a difference spectrum, thus minimizing the systematic errors of theoretical simulations. The problem of several local minima is addressed in the framework of direct and indirect approaches. Acknowledgments. This research was funded by Russian Science Foundation grant number 20-43-01015. References [1] A. A. Guda, S.A. Guda, K. A. Lomachenko, M. A. Soldatov, I. A. Pankin, A. V. Soldatov et al, Catalysis Today 2019, 336, 3. [2] A. Martini, S. A. Guda, A. A. Guda, G. Smolentsev, A. Algasov, O. Usoltsev, M. A. Soldatov, A. Bugaev, Yu. Rusalev, C. Lamberti, A. V. Soldatov, Computer Physics Communications 2020, 250,107064.

Resume : In the nano-age, humans manufacture complex structures atom by atom to design e.g. their specific functionality. Therefore, new tools for the analysis of these structures have to be developed. The HZB microscopy group develops novel methods for X-ray imaging to make use out of the unique interactions of X-rays with matter. For this, X-ray optics for the 10-nm scale characterization of the nanostructure, chemical nature, and composition of materials with high energy resolution are engineered and fabricated. The HZB full-field TXM at the BESSY II U41 undulator beamline allows high spectral resolution of E/ΔE=5000, about 10 nm (half-pitch) spatial resolution and field of views in the range of 10-15 μm [1-4]. With this instrument spatially-resolved NEXAFS studies for material sciences can be performed due to the high energy resolution [5]. Additionally, nano-tomography of cryogenic samples had demonstrated its high potential for life sciences [2]. Conventional spectroscopy methods such as photoemission spectroscopy and X-ray absorption spectroscopy have shown to be particularly well-adapted probes to study electronic properties of nanostructures. However, these conventional spectroscopy techniques typically illuminate areas of 50 µm x 50 μm or larger thus preventing the analysis of a single nanostructure. Spectromicroscopy investigations with nanometer resolution were restricted so far to scanning X-ray microscopes (STXM) or to transmission electron microscopes (TEM) equipped with electron energy loss spectroscopy (EELS). Both methods give no statistical information as they are restricted to small image fields. In contrast, the typical image field in NEXAFS spectroscopy measurements combined with full-field transmission X-ray microscopy (NEXAFS-TXM) is about 10 μm x 10 μm which is large compared to the individual nanoparticle. Therefore, one image stack already contains statistically significant data with nanometer resolution. 1. P. Guttmann, C. Bittencourt, S. Rehbein, P. Umek, X. Ke, G. Van Tendeloo, C.P. Ewels, G. Schneider, Nature Photonics 6 (2012), 25-29 2. G. Schneider, P. Guttmann, S. Heim, S. Rehbein, F. Mueller, K. Nagashima, J.B. Heymann, W.G. Müller, J.G. McNally, Nature Methods 7 (2010), 985-987 3. S. Rehbein, P. Guttmann, S. Werner, G. Schneider, Optics Express 20 (2012), 5830-5839 4. G. Schneider, P. Guttmann, S. Rehbein, S. Werner, R. Follath, J. Struct. Biol. 177 (2012), 212-223 5. K. Henzler, P. Guttmann, Y. Lu, F. Polzer, G. Schneider, M. Ballauff, Nano Letters 13 (2013), 824-828

Resume : This is quite a paradox that a century after the introduction of the Independent Atom Model (IAM - Bragg, 1914), 99.7% of all ca. 1.5mln known crystal structures have been refined using IAM which has some methodological deficiencies. This, among others, includes structures of almost all minerals. In IAM atoms are defined as spheres which do not exchange electron density. In my presentation, I will present a few modern quantum crystallographic aspherical approaches to refinement of structures and localization and refinement of H-atoms[1] such as the Hansen-Coppens pseudoatom formalism applied in multipole modeling [2] and Hirshfeld Atom Refinement (HAR) [3]. I will present a detailed comparison of the results obtained with different approaches as a function of data resolution and models of electron density and compare these with the results of neutron diffraction and theoretical computations. I will also discuss the accuracy and precision of different refinement results. I will also present a few selected examples of quantum crystallographic studies showing, among others, redistribution of charge in minerals under pressure. References [1] Sanjuan-Szklarz, W. F., Hoser, A. A., Gutmann, M., Madsen A. Ø. & Wozniak K. (2016). IUCr Journal, 3, 61-70. [2] Hoser, A. A., Dominiak P. M. & Wozniak K. (2009) Acta Crystallographica, A65, 300-311. [3] Woi?ska, M., Grabowsky, S., Dominiak, P. M., Wozniak, K. & Jayatilaka D. (2016). Science Advances, 2 No. 5, e1600192.

Resume : Silver-based low-emissivity (low-E) coatings are used on transparent building elements (windows) to optimize heat losses. They generally consist of dielectric/Ag/dielectric multilayer stacks, where the thin Ag layer reflects long wavelength infrared (IR), while the dielectric layers both protect the Ag and act as an anti-reflective barrier. The sequence of layers in these films can influence the mechanical properties, which are also strongly related to the nano-scale residual stress distribution in the stack. Residual stress evaluation by combining focused ion beam (FIB) milling and digital image correlation (DIC), using the micro-ring core configuration (FIB-DIC), offers micron-scale lateral resolution and provides information on the depth variation of residual stress, even for non-equibiaxial stress distributions, and hence can be effectively used to characterize low-E coatings. In this work, we propose an innovative approach to improve the depth resolution and surface sensitivity for residual stress depth profiling in the case of ultra-thin as-deposited and post-deposition annealed Si3N4/Ag/ZnO low-E coatings, by considering different fractions of area for DIC strain analysis and accordingly developing a unique influence function to maintain the sensitivity of the technique at is maximum during the calculation. Residual stress measurements performed using this novel FIB-DIC approach revealed that the individual Si3N4/ZnO layers in the multilayer stack are under different amounts of compressive stresses. The magnitude and orientation of the stress change significantly after heat treatment and provides an explanation for the observed differences in terms of scratch critical load. The results show that the proposed FIB-DIC combined-areas approach is a unique method for probing non-equibiaxial residual stresses with nano-scale resolution in thin films, including multilayers.

Resume : High strain rate deformation processes such as ballistic impact, metal cutting or blast loading results in the formation of intense localized regions in the form of narrow bands, called adiabatic shear bands (ASB). They were firstly described by Zener and Hollomon in 1944 [1] as a unique mechanism of a material or structural instability often leading to a catastrophic failure [2] induced by intense localized raise of temperature during the process [3, 4]. However, the details of the mechanism of ASB nucleation, thickening and propagation as well as the crystallographic determinations of these processes are still not well-recognized. In this work, the influence of twinning and micro- and macro- scale shear banding on microstructural and textural changes was investigated in high purity Cu and Cu-14%wt. Al alloy in order to characterize the mechanism of ASB formation. These changes were characterized over a wide range of scales including optical microscopy, scanning electron microscopy equipped with high-resolution electron backscatter diffraction facility (SEM/EBSD) and transmission electron microscopy (TEM). For simplicity the analyses were focused on description of the mechanism of the ASB formation in single crystalline samples of C{112}<111> initial orientation, deformed in channel-die up to 60% at strain rate of ~ 5000 s-1. The detonation of the explosive charge was used for propel of the punch in a channel-die. During plane strain deformation at ‘conventional’ strain rates, two kinds of shear bands are observed depending on the stacking fault energy (SFE). If the precursory obstacles for dislocation motion are fine twin-matrix lamellae, typical for metals with low SFE (e.g. in Cu-14%wt.Al alloy) the SBs are classified as ‘brass-type’. If the precursory obstacles are the elongated dislocation walls of a cell block structure the shear bands are of the ‘copper-type’. They are typically observed in materials with high or medium SFE (e.g. in Cu deformed at ‘conventional’ strain rates). At extremely high strain rates the deformation behavior of both metals is qualitatively similar, since the only brasstype shear bands are observed in Cu and Cu-14%wt.Al alloy. In the both cases the precursory obstacles for dislocations motion are formed by three families of the deformation twins clusters. (It is important to note that the deformed matrix is almost completely consumed by twins). The rotation-induced mechanical instability within narrow areas of the anisotropic structure of twin-matrix layers leads ‘via’ kink-type bands to the formation of welldeveloped shear bands. This is crucial for understanding further texture transformations and for explanation of the crystallographic nature of the ASB. It was shown how the pre-existing sub-structures of twin-matrix layers are incorporated into ASB area, and what kind of the dislocation mechanism is responsible for strain accommodation at macro-scale. From crystallographic point of view it was found that the re-orientation of the {111} twinningplane (also the plane of co-planar slip systems) towards the ASB plane facilitates further dislocation slip in the shear direction. Finally, referring to the idea of local lattice re-orientation [5, 6] a crystallographic model of the ASB formation in fcc metals is proposed. Acknowledgments The authors thank for the financial support of the Polish National Centre of Science (NCN), project no.: UMO- 2018/31/B/ST8/00942. References [1] C. Zener, J.H. Hollomon, Journal of Applied Physics 1944, 15, 22-32. [2] P. Landau, S. Osovski, A. Venkert et al., Scientific Report 2016, 6, 37226. [3] Y. Bai, B. Dodd, Adiabatic Shear Localization : Occurrence, Theories, and Applications 1992. [4] L. Jianguo, L. Yulong,H. Chongxiang, S. Tao, W. Qiuming, Acta Materialia 2017, 141, 163-182. [5] H. Paul, J.H. Driver, C. Maurice, A. Piątkowski, Acta Materialia 2007, 55, 575-588. [6] H. Paul, A. Morawiec, J.H. Driver, E. Bouzy, International Journal of Plasticity 2009, 25, 1588-1608.

Resume : Graphene is a two-dimensional material, which has a great potential for many future applications considering its extraordinary electrical, mechanical, and optical properties [1]. It can be used as a membrane material due to its honeycomb structure, for which the distance between carbon atoms is on the order of 0,064 nm. Thus, the layer of graphene is a barrier material for most gases, excepting hydrogen ions (protons), which has smaller radius [2]. Graphene can also serve as an oxidation protective layer for materials like Cu or Ni [3, 4]. It may influence wetting by liquids as well as dynamics of processes occurring at the interface while deposited onto solid substrate [2]. Interactions between atoms and their spatial distribution near the solid-liquid interface are important factors for the determination of wettability of material as well as crucial in phenomena occurring at the interface in chemical, biological, and technological systems. Especially, graphene seems to be a promising material in electronics industry to limit the diffusion between a substrate and wetting substance, and so, to reduce the growth of compounds such as Intermetallic Compounds (IMCs) which can form at interface [5]. Excessive growth of IMCs is highly undesirable due to the enhanced brittleness, hardness and reduced ductility of the joints. As a consequence depositing layer of graphene could enhance properties of formed joints and their reliability. Wetting is one of the main factor in the case of creating metal contacts. The wetting behavior induced by graphene layer deposition has been investigated mainly using droplets of water and pure metals as wetting substances. So far, some disagreements are found for a correct description of an interaction of graphene with water-based on the experimental results published. Nguyen et al. [6] performed molecular simulations to depict the differences in contact angle between water droplet and substrates such as pure bare Cu and graphene – coated Cu. They also discussed the wetting transparency phenomena in a view of the results found in literature [7]. Only few papers presenting atomistic simulations have been delivered for metal droplets, including interactions with Hg [8], Al and Pb [9], Cu [10], Fe [11], Pd and Ti [12], as well as Ag [13]. However, pure metals are rarely used in technical solutions due to their poor mechanical properties, and thereby, alloys are more convenient solution. As yet, no insight into the interactions between a Cu-based alloy nanodroplets and graphene/metal interface has been published. Moreover, the impact of wetting on the structure-properties interplay has not been investigated. Herein, we discuss structure, composition and interfacial properties of a Cu-Ag nanodroplet in contact with a graphene-coated Cu matrix by atomistic simulations compared with our new experimental results. Structural and dynamic properties of the nanodroplet near the graphene-coated substrate have been studied as a function of graphene structure. The performed atomistic simulations allowed us to understand the structural transitions in the drop by analyzing chemical and topological atom order in Cu –Ag alloy and kinetics at the solid-liquid interface. In this work, we investigated four systems. Copper foil was used as a substrate in all cases: for the two of them, graphene was deposited using chemical vapour deposition method (CVD), in order to obtain diffusion barrier, while two left samples were kept free of graphene layer on the Cu outermost surface. We have used two wetting substances for those variants, such as pure Ag and eutectic Ag-Cu alloy. All of the investigated samples were heated up to T = 1323 K. Our preliminary experimental results clearly show that graphene layer has an impact on diffusion occurring between substrate and the droplets. In case of samples with no graphene deposited on Cu surface, the change in their shape was observed. Namely, a melted alloy of sphere shape was formed from the substrate and wetting substance. Moreover, there was no interface area, which indicates that the reaction between foil and droplets occurred in the entire volume of the investigated material, leading to an alloy formation. Contrary, the interface region could be easily identified for graphene/Cu matrix interface. After heating, samples with a drop adhered to the Cu substrate were observed. Scanning Electron Microscope (SEM) with Energy-dispersive X-Ray Spectrometer (EDS) was used to investigate the microstructure and chemical composition of samples. Images taken with SEM confirm our observations in macro scale. For variants with graphene layer, the interface between droplet and the substrate is well defined. The presence of graphene on the Cu matrix limits the diffusion between substrates and droplets, but it does not hinder Cu substrate before wetting. EDS spectroscopy was also used to determine the changes in chemical composition. For the variants with no graphene layer deposited on a Cu substrate, all of the samples have an uniform and two-phase structure as compared to interfaces with graphene for which only the droplets have two-phase structure. Structure of the samples with graphene layer, was also investigated using Raman Spectroscopy. For all the system configurations, atomistic simulations using molecular dynamics have been performed. We have compared them to the results obtained from the experiment. Acknowledgments Financial support from the National Science Centre Poland, project No 2018/29/B/ST8/02558 References [1] Singh, Virendra, et al., Progress in materials science 2011, 56.8: 1178-1271. [2] Morrow, Wayne K., Stephen J. Pearton, and Fan Ren, Small 2016, 12.1: 120-134. [3] Chen, Shanshan, et al., Nano letters 2011, 11.9: 3519-3525. [4] Raman, RK Singh, et al., Carbon 2012, 50.11: 4040-4045. [5] Smetana, Joe, et al., IPC SMEMA Council APEX. 2011 [6] Nguyen, Chinh Thanh, and BoHung Kim, International Journal of Precision Engineering and Manufacturing 2016, 17.4: 503-510. [7] Rafiee, Javad, et al., Nature materials 2012 11.3: 217-222. [8] Galashev, A. E., Colloid Journal 2015, 77.5: 582-591 [9] Li, Tao, et al., Scientific reports 2016, 6, 34074 [10] Li, Xiongying, et al., Scientific reports 2014, 4: 3938. [11] Yu-Feng, Gao, Yang Yang, and Sun De-Yan., Chinese Physics Letters 2011, 28.3: 036102 [12] Gong, Cheng, et al., ACS nano 2014, 8.1: 642-649 [13] Kumar, Sunil., Carbon 2018, 138: 26-41. Key Words: graphene, interface, wetting, molecular dynamics, structure, diffusion, nano

Resume : High-carbon carbide-free bainitic steels represent a new generation of materials, with optimal strength to plasticity ratio. The excellent properties of the steels are obtained mainly due to the formation of a nanostructure consisting of extremely fine plates of bainitic ferrite, 20-40 nm thick, embedded in the matrix of austenite without carbides at ferrite/austenite boundaries. The nanostructured bainitic steels are generated through isothermal bainitic transformation at low temperatures but above the martensite start one kept for long times (e.g. isothermal heat treatment can take from 2 to 60 days over the range of 125-325°, respectively), adding a significant cost to the product. However, in a commercial scenario, there may be need for more rapid heat treatment in order to limit the cost of production [1-4]. The transformation can be accelerated by (i) the addition of alloying elements like Co and Al, (ii) increasing prior austenite grain size and therefore austenitization temperature [5, 6]. The application of stress at bainitic temperature transformation is another way to reach the same effect. The new modification of the technology will shorten the time of isothermal treatment, reduce the size of nano-bainite colonies and the degree of texture of deformed elements. It is possible through the generation of complex deformation (the direction and intensity of which will be controlled) leading to austenite shear at the transformation temperature, during which the bainite strips are induced alternately in the entire volume [7-11]. The aim of the presented work is to study the influence of various combinations of stress (compressive, tensile and torsion) during isothermal bainitic transformation on microstructure and mechanical properties of the steel. The hot-rolled and spheroidized steel with following composition: Fe-0.74C-2.64Si-1.82Mn-1.00Ni- 0.36Mo-0.21Cr-0.047Al (wt. %) was machined into cylindrical samples of reduced section 10 mm in diameter of and the length of 18 mm. The thermomechanical treatment was conducted using a Bähr MDS 830 simulator dedicated for physical simulation of materials processing described below. After the thermomechanical treatment all samples were held for 10 min at the temperature of deformation and next cooled to RT, but first the specimens were heated to austenitization temperature of 950°C at 2,5 K/s and kept for 3 min. Then, the bainitic transformation procedure was induced by holding the steels at: (i) 230 °C single torsioned by 180° (true strain ~0,32, strain rate 0,03 1/s), (ii) 200 °C, torsion 100° at axial tension (true strain 0,07), stress strain rate 0,07 1/s, (iii) 200 °C torsion 100° (0,07 1/s) at axial compressive stress, strain rate 0,07 1/s. The metallographic study of the all samples after thermomechanical treatment showed that they consisted of bainitic structure. It proved that applying single torsion or combination of torsion with compression/tension at temperature above MS leads to acceleration of bainitic transformation by several times. The detailed identification of structure morphology was not easy using optical microscopy only, therefore the studies of microstructures using higher magnification were performed. The TEM micrographs of the sample after isothermal treatment at 200°C at torsion 100° and axially tensioned, which confirmed the presence of two separate phases: carbide-free bainite, which consisted of mixture of carbon supersaturated ferrite plates with the average thickness of 200-300 nm, and the retained austenite with the thickness of 50-300 nm. The XRD studies confirmed that the concentration of austenite decreased from 29.2 to 24.5 vol.% for the samples after single torsion and after those torsioned and compressed, respectively. The tensile strength test results of the steel samples after austenitization at 950°C/3 min and cooling followed by isothermal treatment with torsion, torsion with tension, torsion with compression, and strength after hot rolling and typical heat treatment 950°C for 30 min, completed with annealing for 72 h at 200°C shows that the highest properties were registered for the sample after single torsion due to the arrangement of bainite plates in one direction. The application of complex stresses led to the decrease of mechanical properties connected with the random direction of plate growth and their mutual blocking during coarsening. When comparing new thermomechanical treatment with the conventional nanobainitic one it could be seen that their mechanical properties were about 30% lower, nevertheless, the heat treatment time was significantly reduced. Further studies are required to optimize the thermo-mechanical treatment of the examined steels. Acknowledgments The research was supported by the Polish science financial resources The National Research and Development Centre, Poland, project title: “Development and implementation of the innovative technology dedicated for the production of ultra-strong steels for key elements of the machines used in the mining industry” No. POIR.01.01.01-00-0418/19-00. References [1] F.G. Caballero and H.K.D.H. Bhadeshia, Current Opinion in Solid State and Materials Science, 2004, 8, 251- 257. [2] M.J. Peet, L.C.D. Fielding, A.A. Hamedany, et al., Materials Science and Technology, 2017, 33, 1171-1179. [3] F.G. Caballero, C. Garcia-Mateo and M.K. Miller, Springer, 2014, 66, 747-755. [4] F. Hu, P.D. Hodgson and K.M. Wu, Materials Letters, 2014, 122, 240-243. [5] F. Hu, K.M. Wu, and H. Zheng, Steel Research International, 2013, 84, 1060-1065. [6] S.J. Lee, J.S. Park and Y.K. Lee, Scripta Materialia, 2008, 59, 87-90. [7] M.X. Zhou, G. Xu, Y.L. Zhang, et al., International Journal of Materials Research, 2015, 10, 1040-1045. [8] M.X. Zhou, G. Xu, L. Wang, et al., Metals 2016, 6, 119-130. [9] M. Zhou, G. Xu, H. Hu, et al., Materials Science and Engineering: A, 2017, 704, 427-433. [10] M. Zhoua, G. Xua, Y. Zhang, et al., International Journal of Materials Research, 2015, 106, 1040-1045. [11] A. Kumar and A. Singh, Materials Science and Engineering: A, 2020, 770, 138528.

Resume : In recent years, the cermet composite coatings produced by cold spraying are often used in various industries such as automotive and aerospace mainly for application to machine part. The main advantage of using this type of coating is very good mechanical properties, obtained by strengthening the metallic matrix with ceramic phase particles. A key aspect is also the high adhesion of the coatings to the substrate, allowing them to work intensively without the effect of peeling off from the substrate [1-3]. The paper presents the analysis of microstructure and strength (Cr3C2-25(Ni20Cr))-5(Ni25C) composite coatings in the interface with the Al 7075 substrate before and after adhesion and three-point bending test. The cold spraying process was performed with an Impact Innovations 5/8 system mounted on a Fanuc M-20iA robotic arm. The tests of coatings using X-ray diffraction using a Bruker D8 Discover diffractometer methods allowed the identification of the phase composition of the sprayed coatings. Characterisation of the microstructure was made based on observations carried out using the scanning electron microscope FEI E-SEM XL 30. To investigate the coating microstructure in micro/nanoscale areas FEI TECNAI G2 transmission electron microscope (TEM) was using. The thin foils for transmission electron microscopy studies were cut with a FIB technique using an FEI QUANTA 3D Dual Beam. The coating hardness test (HV0.3) according to the standard [4] referred to as the Vickers hardness test at low loading force was carried out on a device of the company CSM Instruments SA. The adhesion test was carried out by Positest AT-A device. The three-point bending test was performed with the INSTRON 6025 device. X-ray diffraction studies showed only phases occurring in the initial powder which proves that there were no changes in the phase composition of the coating during the cold spraying process. The microstructure observations revealed a homogeneous distribution of phases in the coating and embedded ceramic particles in the substrate. The hardness of cold sprayed coatings was in the range of 600 – 650 HV0.3. A slight differentiation of the coating hardness was observed, especially between that measured in its middle zone and that near the coating-substrate interface. The study of the adhesion of (Cr3C2-25(Ni20Cr))-5(Ni25C) coatings on the Al 7075 substrate showed that the different preparation (e.g. sandblasting) of the substrate does not affect the final measurement results. Three-point bending tests were carried to investigate the mechanical and bonding properties of the coating to the substrate. (Cr3C2-25(Ni20Cr))-5(Ni25C) coating is a rigid and brittle material and has very limited deformation capability. In the 3-point bending test, the coating matches the bend deformation of the substrate by transversal and interfacial cracking. The denser and finer transversal cracks indicate the coating having a good spalling resistance. Similar relationships were found during mechanical tests of thermally sprayed WC-Co-Cr coatings in [5]. The resent study presents the attempt to test of the adhesion and mechanical properties of (Cr3C2-25(Ni20Cr))- 5(Ni25C) composite coatings in contact with the substrate Al 7075 correlate them with microstructure observation. The coatings showed high hardness, good adhesion to the substrate and a compact microstructure without discontinuities and porosity. Acknowledgments This work was supported by the National Science Centre, Poland (Project No 2017/25/B/ST8/02228). References [1] A. Góral, L. Lityńska-Dobrzyńska, M. Kot, Journal of Materials Engineering and Performance, 2017, 26, 2017-2119. [2] M. Książek, L. Boron, M. Radecka, et.al., Journal of Materials Engineering and Performance, 2016, 25 3185-3193. [3] K.I. Triantou, D.I. Pantelis, V. Guipont, et al., Wear, 2015, 336-337, 96-107. [4] PN-EN ISO 6507-1:2018-05 Metallic materials – Vickers hardness test – Part 1: Test method. [5] M. Gui, R. Eybel, B. Asselin, et al. Journal of Materials Engineering and Performance, 2015, 24, 1347- 1356.

Resume : Inconel 625 is a nickel-based superalloy characterized by high strength and corrosion resistance at high temperature up to 800 °C. These features made it to be commonly used in the chemical industry, aerospace and power plant applications. On the other hand, Inconel 625 exhibits high hardness, poor machinability and low thermal conductivity, thus it is difficult to fabricate components with a complicated shape. These problems can be overcome through the use of additive manufacturing. Laser-based directed energy deposition (L-DED), one of the major additive manufacturing processes, consists of melting metal powder fed by nozzle by a focused laser beam. This process is mainly used to repair and recover metal parts, however, it can be also used for fabrication of the whole parts. Application of L-DED Inconel 625 at a high temperature requires investigation of its influence on microstructure and hardness. Therefore, the aim of this study is a microstructural investigation and microhardness measurements of Inconel 625 additively manufactured using the L-DED method, subjected to stress relief annealing at a temperature of 870 °C for 1 hour and subsequently annealed at a temperature of 600, 700 and 800°C for 5 hours. Microstructural investigation was carried out by light microscopy, scanning electron microscopy combined with microanalysis of chemical composition by energy-dispersive X-ray spectroscopy. Phase identification was performed with the use of electron diffraction in the transmission electron microscope. For microhardness measurements, the Vickers HV1 method was used. It was found that after stress relief annealing L-DED Inconel 625 exhibits fine dendritic microstructure, which is typical for metal alloys processed by this method. Precipitates of the secondary phases, which are irregular, globular and plate-like shaped, segregate to the interdendritic regions (fig. 1a). They have been identified as Laves phase, MC and M23C6 carbides. After annealing at a temperature of 600 °C, there were no visible differences in microstructure comparing to stress-relieved condition (fig. 1b). In turn, after annealing at a temperature of 700 °C a lower amount of the irregular-shaped precipitates of the Laves phase was noticed, with a simultaneous increase of the population of plate-like precipitates of the delta phase enriched in Nb and Mo. Moreover, the dendritic microstructure disappeared due to the homogenization of the chemical composition (fig. 1c). Further increasing of the annealing temperature up to 800 °C led to the disappearance of the Laves phase in favour of the further precipitation and growth of the delta phase precipitates (fig. 1d).

Resume : Two gilded Kaiser Wilhelm memorial medals with similar appearance were studied using nondestructive and destructive techniques to determine the chemical composition of the base materials. The two medals consist of low-alloyed Cu (medal B) and CuZn7Sn3 (medal A), with some additional trace elements. We conclude that apart similar appearance medals A and B were manufactured differently, most probably in different mints.

Resume : In many industries, stress engineering plays an important role for the development of new products and materials. Microprocessors and microelectronic products for example are highly complex structures made from numerous materials with specific thermal and mechanical properties. Because of the different thermal expansion coefficients of the materials, mechanical stress occurs during manufacturing and use, which could result in fracture and failure of the products. Therefore, it is necessary to characterize these materials and also the influence of mechanical stress on the products. A common method to apply mechanical stress is loading components and test structures with the 4-point bending (4PB) mode. The advantage of 4PB is the constant bending moment between the inner support points. A novel rotational 4- point bending tool (rot4PB, Figure 1) for in-situ scanning electron microscopy (SEM) uses rotational sample clamps instead of standard fixed grip sets that are displaced towards each other in conventional tools. This enables a low building height for various applications while achieving high loads. The tool is designed for use in atmosphere in combination with additional analytical tools and for vacuum use, e.g. in SEM/FIB tools. Here, the unique working principle [1] allows various bending modes and alternating compressive and tensile stress on sample surfaces without changing the setup and without handling the sample outside the vacuum chamber. The mechanical stress on the sample surface can be determined at any point with the knowledge of the sample geometry through the measurement of the actual torque on both sample clamps. The rot4PB tool can keep the bent state of a specimen due to a high holding moment even when powered off. This enables easy transfer in additional tools such as SEM/FIB, Raman spectroscopy, EBSD, nanoindentation, SPM and other techniques to study the sample surface of a specimen. Hence, it is possible to conduct indentation experiments on a bent specimen, transfer the setup from the nanoindenter tool to an SEM to investigate the indents in the SEM. This workflow was used to investigate the crack length of indents on a thin film samples with an intrinsic compressive stress (Figure 2). Nanoindents were performed to calibrate FEM simulations where the fracture properties of the thin film were investigated. In these simulations the crack length must be greater than the indent length to get reasonable results. Without the application of additional tensile stress with the rot4PB tool the crack length was too small and did not meet this requirement [2]. The applied tensile stress was validated by Raman spectroscopy and correlates well with the internal calculation of the control software. Conclusion An in-situ rot4PB device was shown with novel applications, highlighting the possibility of linked experiments in various tools while maintaining the sample stress state. Acknowledgement Funding of parts of this work by the German BMWI (Bundesministerium für Wirtschaft und Energie) in the frame of the Important Project of Common European Interest (IPCEI) is greatly appreciated. References [1] C. Sander, M. Gall, A. Clausner, F. Macher, E. Zschech, patent EP 3 601 999 B1, “Device for Carrying out Bending Tests on Panel-Shaped or Beam-Shaped Samples“ [2] S. Ananiev, P. Altieri-Weimar, C. Sander, A. Clausner, EuroSime 2020, “Determination of Fracture Properties of Thin Dielectric Films by Nanoindentation”

Resume : Compared with composites, the possibilities to achieve an adequate combination of density, strength, toughness, or damping properties of monolithic metallic materials, are limited. Therefore, in the recent years, an increasing global demand for novel materials is observed. The market requirements led to rapid development of metal matrix composites (MMCs), which possess unique properties, often difficult to achieve in bulk metals and their alloys, e.g. high specific strength. As a rule of a thumb, the functional properties of MMCs strongly depend not only on selection of the metallic matrix or processing route of a composite, but also on the size, shape, and amount of the added reinforcement phase. Currently, when developing novel MMCs, great attention is being paid to exploring the possibilities for using reinforcement materials of natural origin. For example, the sustainable sources of silica, which is often utilized in MMCs as a filler, are rice husk ash or wheat straws [1]. The advantage of using natural reinforcement materials in MMCs production is the possibility not only to obtain cheaper solutions, but also to responsibly manage waste from the agricultural industry. Nowadays, the silica nano- and microparticles are often proposed as fillers for production of aluminium matrix composites (AMCs). Nevertheless, due to poor of wettability of silica-aluminium system [2], it is challenging to process the Al-SiO2 mixture so that a composite of sufficient quality will be obtained. Therefore, up to date, various processing methods of those systems were introduced. For example, the SiO2-reinforced AMCs are currently produced by powder metallurgy [3] or stir casting [4] methods. In this study, a novel approach to producing SiO2-reinforced AMCs is proposed. As a matrix, pure aluminium was used, while the reinforcement – a natural ceramic filler material – consisted of food-grade diatomaceous earth (DE). Diatomaceous earth has a powder-like structure and consists of frustules – the three-dimensional, nanoscaleporous diatom cell walls, formed of silica. To our knowledge, DE-reinforced AMCs were not produced before. For SPS sintering, four various mixtures of substrate powders (diatomaceous earth and aluminium) were prepared, with the following content of diatoms: 0, 10, and 30 vol. %. Commercial aluminium powder (grain size 44÷420 μm) was supplied by Alfa Aesar (Thermo Fisher GmbH, Germany), while diatomaceous earth was purchased from Perma Guard. Before consolidation, both substrates, in form of frustules and aluminium powders, were mixed in a mechanical stirrer for 1 h. The AMCs were developed by the powder metallurgy route, using spark plasma sintering (SPS) technique. In SPS, pulsed AC or DC current directly passes through the graphite die, where the mixture of the substrates are placed. Therefore, in contrast to the conventional hot pressing, the heat is generated inside the die. Due to that, compared to conventional techniques of powder consolidation, remarkably high heating or cooling rates (up to 1000 K/min) are achieved. In this study, a HP-D-10 (FCT System GmbH, Germany) SPS system was used (Figure 1). For sintering, about 3 g of powder mixture was loaded into a graphite die (Ø10 mm), the internal surface of which was covered with a graphite foil sheet, to avoid direct contact between the powder compact and the graphite die. A summary of sintering parameters is given in Table 1. To assess the influence of DE content on the mechanical properties of Al composites, the small punch technique (SPT) was used. The tests were carried out using a Zwick/Roell Z005 universal testing machine, equipped with a 5kN load cell. For the deflection measurements, an electromechanical extensometer MTS 634-12F-25 was used. For each sample, the force-deflection curves were collected. Based on the force-deflection curves, yielding force Fy, ultimate force Fu, as well as deflection at ultimate force A, were calculated. Moreover, using buoyancy method, density of the as-received samples was calculated. All samples were also subjected to scanning microscopy observations (SEM-FIB, Thermo Scientific Scios 2). According to the results, SPS is a suitable method for Al-DE composites production. The best material quality, in terms of distribution of diatoms in the matrix, was achieved in samples obtained in series II. Moreover, the yielding force Fy was similar in all tested specimens, irrespective of the DE content. The ability of matrix to yield in DE-modified samples was confirmed also in SEM observations. On the other hand, as a result of diatom addition, the Fu of aluminium was substantially decreased. The achieved decrease in density did not compensate the significant drop in specific strength of the obtained composite materials. Acknowledgments The research is financially supported by the Federal Ministry of Economics and Energy by resolution of the German Bundestag (CORNET, IGF-Nr.: 248EBR). The financial assistance for this research, made within the project CORNET/26/3/2019 (MECODIA), was partially obtained from the National Center for Research and Development, Poland. References [1] S. D. Saravanan, M. Senthilkumar, S. Shankar, Tribology Transactions 2013, 56, 1156. [2] P. Shen, H. Fujii, T. Matsumoto, K. Nogi, Metallurgical and Materials Transactions A 2004, 35, 583. [3] S. Mohan, G. Gautam, N. Kumar, R. K. Gautam, A. Mohan, A. Kr. Jaiswal, Composite Interfaces 2016, 23, 493. [4] B. P. Kumar, A. K. Birru, Transactions of Nonferrous Metals Society of China 2017, 27, 2555.

Resume : The corrosion of reinforcing steel in concrete structures is a serious problem from the perspective of both safety and economy and affects directly the sustainability and life-time of the infrastructure. Corrosion of reinforcing steel is one of the most common degradation processes which can affect reinforced concrete structures causing their loss of serviceability, needs for repairs, premature pulling down, and in extreme cases can lead to structural collapse (e.g. the Genoa bridge collapse in 2019). Concrete provides a highly alkaline electrolyte encapsulated in its pores, and in such conditions steel remains passive. However, chlorides and atmospheric carbon dioxide penetrate into the pores and promote corrosion when reaching the reinforcement, which weaken the concrete structural properties inducing the cover cracking and the loss in steelconcrete bond. Chloride induced corrosion of reinforcing steel is one of the main causes of structural concrete deterioration, and therefore, it is responsible for a large share of the cost for the rehabilitation of concrete structures [1]. Since the concrete cover plays a crucial role in protecting the steel rebars, acting as a barrier for chlorides ingress, the durability of the concrete structures depends on the transport properties of the material. The transport of chlorides in concrete is a complex process with different parameters influencing the rate of penetration of ions. The most important one is the effective diffusion coefficient. It is defined based on the diffusion coefficient of the ions in a pure solution but it depends on the morphology of the porous material too. This morphology (microstructure) of the material is described quantitatively by porosity (ϕ), tortuosity (τ) and constrictivity (ẟ) parameters. Simplified 1D models [2,3] neglect that concrete is a multiphase porous material with a 3D microstructure including channels (capillary and gel pores) for ionic transport. Therefore, we model ion transport in a real 3D cementitious material based on microstructure information from nano X-ray computed tomography (nano-XCT) measurements. A laboratory full-field transmission X-ray microscope (Xradia Ultra 100) was used at a photon energy of 8 keV with a field of view (FOV) of 65μm that provides a spatial resolution of sub-100 nm [4]. A small sample was carefully prepared without damaging it, to acquire image data within the FOV nondestructively. The tilt series for tomography covering an angular range of 180° consisted of 601 projections, with an exposure time of 110 s for each projection.

Resume : Diatomaceous earth is a biogenic siliceous sedimentary rock, which mainly consists of fossil diatom frustules. Diatom frustules are potential materials for nanotechnology applications [1, 2], e.g. diatomite filters, diatom-based biosensing devices etc. In order to engineer the diatom material, their hierarchical microstructure and mechanical behavior need to be fully understood. Here, the hierarchical architectures of fossil diatom frustules (Genus from Ellerbeckia and Melosira) are studied by nano X-ray computed tomography (NanoXCT) [3, 4], transmission electron microscopy (TEM) and focus ion beam/scanning electron microscopy (FIB/SEM). In-situ micromechanical experiments with uniaxial loading were used to investigate the mechanical behavior. With the quantitative study, the following microstructural dimensions and features are analyzed: (i) The surface and the inner structures of the selected frustules are obtained by nanoXCT. (ii) The size of ordered features on the round copulae of Ellerbeckia is measured at the unrolled cylinder wall. (iii) Structure information of the tube process and inter-valve face is acquired by FIB cutting and TEM with high spatial resolution. (iv) Element distributions of several important structure areas, i.e., tube process, center of the valve face, and the connection area of the epivalve and hypovalve, are obtained by energy-dispersive X-ray spectroscopy (EDX). (v) Nanopores of about 15 nm are revealed by TEM. (vi) There is the sealed layer structure on the valve inner face and connection area of the epivalve and hypovalve. Here is the figure 1 to show the microstructures of Ellerbeckia imaged by nanoXCT. In order to get the maximal loading force and the crack propagation behavior of these diatom frustules, uniaxial compression tests were performed in-situ in X-ray microscope on the surface of the valve face and on the copulae area. Analysis of the mechanical test reveals that the force and strain appear to be strongly dependent on the size of the frustules. The maximal force decreases as the cylinder diameter of the frustules decreases. For cylinder diameters of 80 µm, 69.5 µm, 62.5 µm and 46 µm, the corresponding maximal loading forces are 82 mN, 45 mN, 44 mN, and 20 mN, respectively. Furthermore, the cracking process of the diatom frustule is monitored by a series of radiographs. It is found that the crack initiates along the thinnest structure or the linkage structure (Fig.2). The tomographies were acquired before/after the compression test to elucidate the structure change before/after loading the force as well. Acknowledgments The research is financially support by the Federal Ministry of Economic Affairs and Energy on the basis of a resolution of the German Bundestag (CORNET, IGF-Nr.: 248EBR). We thank Prof. Małgorzata Grądzka-Dahlke’s group from the faculty of Mechanical Engineering at Białystok University of Technology for supplying the diatomaceous earth. References [1] D. Losic, J. G. Mitchell and N. H. Voelcker. J. Nanosci. Nanotechnol. 2006, 6, 982. [2] M. Diab, T. Mokari. Adv. Mater. 2018, 30(41), 1706349. [3] Q. Li, J. Gluch, P. Krüger, et al. Biochem. Biophys. Res. Commun. 2016, 479, 272-276. [4] I. Zgłobicka, Q. Li, J. Gluch, et al. Sci. Rep. 2017, 7, 9086.

Resume : For high-power semiconductor devices, a binary alloy of titanium and tungsten (TiW) is often used as a diffusion barrier to isolate the copper metallisation interconnects from the silicon substructure. A diffusion barrier is necessary as copper rapidly diffuses into silicon at low temperatures (<200 °C), which can lead to premature device failure. Despite the effectiveness of TiW diffusion barriers, a detailed characterisation study on the system has yet to be performed. Exposure to high-temperature events, both experienced within the manufacturing route and during service can encourage the segregation of titanium out of the TiW alloy and into the copper. This mechanism can allow copper to bypass the barrier, leading to the formation of copper silicides which act as the epicentre of a host of thermo-mechanical failure mechanisms. Additionally, a commonly employed tactic to improve the copper blocking efficiency of the barrier is to expose the layer to air by a vacuum break, prior to copper deposition, which is thought to “decorate” the grain boundaries with oxides. Both this titanium diffusion mechanism and the oxidation behaviour of TiW are critical properties that have a direct influence on the performance and reliability of the device. In order to achieve improvements in these areas, TiW and its associated interactions must be better understood. Here, un-patterned, Si/SiO_2/TiW thin film stacks, with varying titanium concentrations and annealed for varying durations at 400 °C under an argon atmosphere were characterized using a combination of soft and hard X-ray photoelectron spectroscopy (SXPS and HAXPES). Combining SXPS and HAXPES provided the opportunity to study the chemistry across the TiW film both from a surface (< 5nm) and bulk (< 20 nm) perspective, respectively. Samples were annealed to study the titanium diffusion mechanism and in parallel, the same samples were left exposed to the ambient environment to study the oxidation behaviour. Results showed that an increase in the titanium concentration was observed at the surface with increasing annealing duration. An increase of up to 17 at.% in the titanium signal was observed after only 0.5 h of annealing, highlighting the severity and speed of this diffusion mechanism. The accumulation of titanium at the surface accelerated the rate of oxidation due to the high chemical affinity of titanium to oxygen. Full metal to oxide conversion was not observed in either case of titanium or tungsten and metallic features were still retained. Multiple titanium and tungsten states were also observed but the rate of titanium oxidation was significantly higher than tungsten. This combinatorial characterisation approach worked well as the respective techniques complemented each other’s shortcoming. Additionally, the results provided a detailed account on the oxidation behaviour of the TiW interface, which will be directly fed back to industry, optimizing future device technologies.

Resume : Titanium prosthetics are commonly used devices in orthopedics and craniofacial surgery applications. Coating of orthopedic titanium implants with biocompatible hydroxyapatite nanoparticle (HANP) is a promising approach to facilitate bone cells anchorage and osteointegration. Herein, we report synthesis of hydroxyapatite nanoparticle (HANP) in presence of a malonic acid amphiphile (MA) through biomineralization approach and its coating onto titanium implant for potential bone tissue engineering application. HANPs synthesized by in situ precipitation were subjected to FTIR analysis, wherein the characteristic peaks at 3568, 1461, and 1041 cm-1 were observed. In PXRD analysis, the prominent peaks at around 2θ = 26° and 2θ = 33° indicated MA-mediated generation of hydroxyapatite phase. FESEM and FETEM analysis revealed that HANPs were spherical-shaped and 22-27 nm in size. HRTEM indicated that the lattice distance for HANPs was 0.29 nm, while the crystallinity of HANPs was validated by SAED. TGA indicated degradation of HANPs from 20°C to 800°C, with 87% residual mass, while BET analysis revealed that HANPs had a surface area of 90 m²/g and an average pore size of 4.04 nm. The surface of titanium (Ti) wire was coated with type-I collagen and HANPs (1mg/ml concentration) and characterized by FESEM-EDX and FTIR analysis. FESEM analysis revealed a homogeneous appearance of HANPs deposited onto the surface of Ti wire. Subsequently, EDX analysis confirmed the presence of Ca, P and O elements. FTIR analysis revealed the presence of characteristics peaks of HANPs in case of coated titanium wire. The HANP synthesized by malonic acid amphiphile was non-toxic to cultured MG-63 osteosarcoma cells. Proliferation of MG-63 cells over HANP-coated Ti wire was evidenced by resazurin assay and calcein-AM staining. An increase in alkaline phosphatase activity and enhanced expression of collagen I (Col-I), alkaline phosphatase (ALP), Runt-related transcription factor 2 (Runx2) and osteocalcin (OCN) osteogenic differentiation markers was noted for MG-63 cells growing on HANP-coated Ti wire. In addition, alizarin red S staining indicated calcium mineral formation. It is envisaged that malonic acid amphiphile-mediated synthesis of HANP outlined herein holds interesting prospect to generate biocompatible nanomaterial-coated Ti wire implant for bone tissue engineering applications.

Resume : It is shown that silicon nanostructures can be used as a template for the creation of gold nanostructures of various morphologies. These nanostructures are used as surface-enhanced Raman scattering (SERS) sensors. The SERS activity and the chemical stability of gold (Au) allows the Au@Si substrate to possess perfect sensitivity, homogeneity, reproducibility and chemical stability. Here the silicon nanowires matrix (SiNWs) was obtained by the use of metal-assisted chemical etching (MACE) of boron-doped single crystalline Si wafer. For the formation of Au nanoparticles (Au NPs) the SiNWs was immersed in AuCl3 and HF solution as described in [1, 2]. The resulting samples were examined using Carl Zeiss ULTRA 55 FE-SEM scanning electron (SEM) microscopy and Confotec ™ MR350 confocal Raman micro-spectroscopy. The resulting SEM image clearly shows Au NPs are about 100 nm located on SiNWs. The samples were used for detection 4-mercaptopyridine (4-MPy) in different concentrations. The possibility of diagnosing 4-MPy up to a concentration of 1 nM has been demonstrated. The research was funded by the Russian Science Foundation (grant number 20-12-00297). [1] Zukovskaja, O., Agafilushkina, S., Sivakov, V. et. al. Rapid detection of the bacterial biomarker pyocyanin in artificial sputum using a SERS-active silicon nanowire matrix covered by bimetallic noble metal nanoparticles. Talanta. 2019, 202, 171-177. [2] Osminkina, L.A., Zukovskaja, O., Agafilushkina, S.N et. al. Gold nanoflowers grown in a porous Si/SiO2 matrix: The fabrication process and plasmonic properties. Appl. Surf. Sci. 2020, 507.

Resume : During the last years, the high entropy alloys (HEAs) have attracted more attention than conventional alloys due to their improved strength, mechanical properties even at elevated temperatures, oxidation resistance, ductility and fracture toughness. In this study, machine and automotive industry was targeted, where medium-to-high friction and wear resistant coatings are needed. For this purpose, coatings of metallic and carbo-nitride TiCrCoNiV high entropy alloys were developed by a hybrid technique consisting on magnetron co-sputtering of high purity elemental targets in inert and reactive atmospheres of Ar and Ar CH4 N2. A con-focal magnetron sputtering system was used, AJA ATC-ORION, equipped with five unbalanced magnetrons fed by HiPIMS (Cr target), DC (Ti and V targets) and RF (Co and Ni target) sources. The coatings were investigated in terms of elemental and phase composition, morphology, density and roughness by EDS, XRD, AFM, XRR. Moreover, a mechanical behaviour at micro and nano scale was performed. Nanoindentation was carried out by measuring the load-displacement curves characteristic to each deposition type. Hardness (H) and reduced modulus (Er) were obtained by using a maximum indentation load of 6 mN. Adhesion was evaluated by progressive load scratch test and critical load for each deposition was determined. Further, multi-pass scratch test was used to evaluate wear behaviour at subcritical loads. Surface profilometry, used to assess the coatings thickness, showed a media of about 2.5 µm. The metallic HEA coatings showed an increased friction coefficient of about 0.35 at an applied force of 1 mN, while the carbon richest carbo-nitride HEA showed the largest values of H (18.0 GPa) and Er (213.4 GPa). The highest adhesion and the calculated wear rate (obtained after 10 passes by applying 2 N constant load) were exhibited by the metallic coating. This work was carried out within the M.ERANET-6059-TriboHEA project funded by The Ministry of Education and Scientific Research, Romania, UEFISCDI Programme 3, grant no. 113/2019 and by The Ministry for Economic Development and Infrastructures, Basque Country, Spain, Hazitek Programme, grant no. ZL-2019/00622.

Resume : Different concentrations of Ag/Au alloys were synthesized using “green chemistry” approach. The aim of the study was to determine the appropriate concentration of Au that provides protection against oxidation for the silver nanoparticles, while maintaining the enhanced plasmon properties of the latter. We started from two liquid solutions containing: (a) Au nanoparticles (commercially available under the name Bright Brushing Gold®) and (b) Ag extracted in lavandin oil from silver conducting paste. The two solutions were mixed in different proportions in order to obtain three types of alloys: (1) 20%-Ag:80%-Au; (2) 40%-Ag:60%-Au and (3) 50%-Ag:50%-Au. The solutions were thermally treated at 12000C and at 1800C. The resulting deposit was investigated using SEM, EDX and Raman spectroscopy. Keywords: silver-gold alloy, plasmonic properties, surface enhanced Raman scattering, green chemistry Acknowledgements: This work was supported by a grant of the Romanian Ministry of Education and Research, CNCS - UEFISCDI, project number PN-III-P1-1.1-PD-2019-1134, within PNCDI III, CORE Programme, Ctr. 18/N/2019 and Contract nr.19PFE/17.10.2018 financed by Ministry of Research and Innovation.

Resume : Resolving the redox reaction of metallic nanoparticles is crucial to improve their application in many different fields. The in situ or operando TEM technology is attractive in observing sample dynamics that provides unique insights into the reaction mechanisms. However, the data acquisition is challenging due to inherent imaging instability caused by external stimuli of both chemical and physical fields (e.g. temperature). The redox reaction has not been precisely captured due to compromised data quality or missing moments of sample dynamics. The advanced TEM platform AXON enables intelligent control of such experiment, ensuring that sample stays locked in place as environmental conditions change, delivering unprecedented results even at extreme magnifications. Along with fully synchronized data collection, the redox of copper (oxide) NPs is well-resolved in space and time triggered by a variety of thermal and chemical environments. The nanoscale Kirkendall effect, formation of oxidation islands and reduction densification was visualized in real time. AXON enhanced analysis and resolution capability of TEM and empowers new types of research to unlock applications in relevant fields. References [1] J. Cao & M. Willinger, In situ observation of oscillatory redox dynamics of copper Nature Communications 2020, 11, 3554.

Resume : Scanning electron microscopy (SEM) and atomic force microscopy (AFM) are two of the most used, complementary techniques for surface analysis at the nanoscale. Thus, combining them by integrating a compact AFM into SEM brings novel possibilities for true correlative imaging and advanced multi-modal sample characterization that would be often unfeasible using each imaging modality separately. LiteScope is produced by the NenoVision company and represents a compact AFM, which is designed to be integrated into a large variety of SEMs in a plug-and-play manner. In general, the strength of the AFM-in-SEM hybrid system lies in combining the AFM modes (3D topography, electrical, mechanical and magnetic measurements) with SEM capabilities (fast imaging with wide resolution range, chemical analysis, surface modification using FIB/GIS etc.). Further benefits include precise AFM tip navigation by SEM to the region of interest, roughness evaluation and in-situ conditions, which is essential for sensitive samples and minimizes sample handling. Uniquely, LiteScope design enables simultaneous acquisition and correlation of AFM and SEM data by NenoVision’s proprietary technique called Correlative Probe and Electron Microscopy (CPEM). CPEM functionates in a way that the electron beam and AFM tip keep a constant offset and remain static during the image acquisition. The scanning movement is conducted by a piezo scanner that carries the sample. This ensures simultaneous SEM and AFM data collection in the same coordinate system and with identical pixel size. The resulting 3D CPEM view can combine multiple channels, both from AFM and SEM, enabling thorough sample analysis and clear data interpretation for specific applications. In conclusion, the AFM-in-SEM strategy benefits from the complementarity of both techniques alongside significant savings both in time and resources. Also, it opens completely new possibilities for advanced data correlation and measurements in variety of industrial and research applications, such as semiconductors, material-, biological- and earth-sciences.

Resume : Intermetallic compounds are promising materials in many application areas [1]. Due to their unique structural properties, these alloys show catalytic properties that can be applied for various chemical transformations. The development of catalysts based on intermetallic compounds may limit the use of noble metals for this purpose. Catalytic properties of intermetallic phases result from the presence of active centres that are atoms of the transition metal distributed in well defined structure. One of quick developing groups of materials are phases based on aluminium. Implementing these materials for industrial applications would benefit from the low cost and wide availability of the constituent metals [1,2]. Al13TM4 (TM- transition metal) compounds, which are also approximants of decagonal quasicrystals, are phases of interest because of various inequivalent adsorption sites and a chemical bond network that provides segregation resistance and structural stability [3]. The atoms arrangement causes site isolation, which ensures the presence of electronic and geometric effects responsible for high activity and selectivity of the catalyst. Previous studies confirm the possibility of use cobalt and iron as a transition metal with encouraging result. The phases based on these metals have high selectivity in reactions of semihydrogenation of unsaturated hydrocarbons [4]. Preparation of materials of quasicrystal approximant structure is exigent due to the narrow compositional range of these phases in Al-Co system and segregation of its components [5]. To avoid such difficulties rapid solidification methods are used. In the present work the melt spinning method was proposed. This technique of production intermetallic phases has not been widely used so far, so the aim of this study is to examine the microstructure of the obtained ribbons and testing of their catalytic properties. The Al75.8Co24.2 (in at. %) ribbons, corresponding to Al13Co4 phase have been produced by melt-spinning technique. The ribbons were obtained in the form of fragmented, brittle flakes. Heat treatment was carried out to obtain a single-phase structure. The ribbons were annealed at 900 °C for 78 h. Thin foils were prepared for as spun ribbon flakes and after annealing. The microstructure of the ribbon was examined using FEI scanning electron microscope (SEM) E-SEM XL30 and FEI transmission electron microscope (TEM) Tecnai G2. Catalytic properties tests were carried out by hydrogenation of phenylacetylene reaction, a model process for the selective hydrogenation of alkynes to alkenes, in an agitated batch glass reactor. A gas chromatograph (Clarius 500, Perkin Elmer) with He as a carrier gas was used for analysing the reaction mixture. The SEM micrograph of the cross-section of the as spun Al13Co4 ribbon revealed the columnar structure resulting from directional solidification in the examined material in direct contact with the rotating drum, which contains the elongated grains with the second phase located between them. More uniform grains were observed near the free surface of the ribbon due to the reduced cooling rate in this region. The microstructure observed by TEM confirms the presence of two phases: dark grains containing 74 at.% of Al and 26 at.% of Co and light regions enriched in aluminium, with average composition 83 at.% of Al and 17 at.% of Co. The selected area diffraction patterns (SADP) allowed to identify the crystal structure of the observed phases. It was found that the grains correspond to the quasicrystalline phase. Similar structures of decagonal quasicrystal were observed in the Al-Co alloys by Ma [6]. The area between the grains was identified as monoclinic Al9Co2 phase (space group P21/c and lattice parameters a=0.6216 nm, b=0.6288 nm, c=0.8559 nm, β=94.77°). Annealing at 900 °C for 78 h caused the transformation to a single-phase structure of the grains composed of Al77Co23. Based on the SADP’s these grains were identified as orthorhombic Al13Co4 phase (space group Pnm21, a=0.8158 nm, b=1.2342 nm, c=1.4452 nm). The characteristic for this phase stacking faults are visible inside all grains. In the catalytic tests the Al13Co4 intermetallic compound was used in both forms, as received and after annealing. Before the experiment the flakes were pulverized in a vibration ball mill and sieved to separate powder fractions. For catalytic tests the fraction below 32 μm was selected to increase the active surface area. All the ribbons catalyse the hydrogenation reaction with different conversion rate and selectivity depending on the microstructure and process conditions. It was found that for annealed ribbons with single-phase structure better results of the catalytic reaction than in as spun state were registered. A higher degree of conversion for both states of material was achieved at 60 °C. The highest degree of conversion 31% was obtained for annealed Al13Co4 at 60°C and the highest selectivity to styrene was registered for annealed ribbon at 25°C. Rapid solidification and annealing enabled obtaining single-phase orthorhombic Al13Co4 structure, which provide higher catalytic performance than multiphase material. Further investigation will be focused on the enlargement of specific surface area. It should improve the activity of catalyst and increase the degree of conversion in the reaction. Acknowledgments This work was supported by the National Science Centre Poland, within the project No. 2017/25/B/ST8/02804. References [1] S. Furukawa, T. Komatsu , ACS Catalysis 2017, 7, 735–765. [2] M. Armbrüster, R. Schlögl, Y. Grin, Science and Technology of Advanced Materials 2014, 15. [3] E. Gaudry, et al. Journal of Materials Chemistry A 2020, 8, 7422–7431. [4] L. Piccolo, et al. Science and Technology of Advanced Materials 2019, 20, 557–567. [5] P. Priputen, et al. Journal of Alloys and Compounds 2015, 647, 486–497. [6] X. L. Ma, K. H. Kuo, Metallurgical Transactions A 1992, 23, 1121–1128.

Resume : Recycling of refractory ceramics is gaining momentum given environmental concerns due to industrial waste accumulation as well as dwindling supplies of refractory raw materials. It thus become crucial to develop strategies allowing for ceramic waste to re-enter the industrial circle (circular economy). Some limitations for reusability of spent ceramics are imposed nonetheless by the extent of mineralogical damage, e.g. contamination with slag, partial infiltration with steel, increased fraction of low density volatile hard to sinter powders, typically accompanying the industrial on-site steel making processes. Therefore, the elaboration of any new recycling strategy of the industrial ceramic waste requires a detail estimate of the reusability of such materials including their microstructure and phase composition assessment. However, analysis of this multi-component ceramic pose a challenge for scanning electron microscopy due to low contrast differences between respective phases and excessive charging. Thus, in this work a low voltage scanning electron microscopy is implemented for the characterization of the spent refractory pastes. Few stages of the industrial process are reconstructed on the laboratory scale to pin point the phase evolution. The performed investigations helped to acquire a set of preliminary data needed for development of a feasible technology of ceramic waste recycling. Acknowledgments The research was co-financed by the Polish Ministry of Science and Higher Education in the frame of the project DWD/3/29/2019 “Doktorat Wdrożeniowy”

Resume : Technical development is closely related to the development of knowledge in the design, production, and processing of new material functions [1]. Particularly intensive development concerns new materials in the areas of the automotive industry [2] and aviation [3], but mostly in the tool industry [4]. Advanced solutions for the production of thin anti-wear coatings are of great importance. New anti-wear coatings are to enable modification of functional properties of machine and tool parts, thanks to which they can operate in increasingly difficult conditions, e.g. high mechanical and thermal loads, intensive wear, or harmful corrosive environment. Currently, extensive research is being carried out on ultra-hard thin anti-wear coatings [5-8]. Titanium diboride TiB2 is characterized by high hardness, Young's modulus [9] and high thermal conductivity [10], as well as high chemical resistance [11] and thermal resistance [12]. TiB2 coating is characterized by a very low affinity to aluminium [13], which indicates that it can be a good anti-wear agent as a cutting tool material for machining aluminium alloys. However, despite very interesting properties of the coating, TiB2 has not found a wide commercial application due to very high brittleness caused by a high state of the inherent stress. The aim of this work was to investigate the influence of doping TiB2 coatings by tungsten on structure and properties. TiB2 coatings with various W contents (0, 3, 6, 10%) were fabricated using the magnetron sputtering method from TiB2 and W targets. The chemical and phase composition, microstructure, and mechanical properties, were investigated using different techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) with analysis EDS and nanohardness. The results showed that the microstructure of the W-TiB2 coating change with doping by W. With an increase of contents W decreases the crystalline size and the preferential orientation is visible. TEM analysis indicated the nanocrystalline columnar structure witch change also with tungsten contents. In coating with W =3, 6% we observed only TiB2 grains encapsulated by a region rich in tungsten. In coating with 10% W, the structure reminds nanocomposite Ti-B-W. The nanohardness increases with growth of doping W. The change in hardness is also manifested in the observations of cracks around the place after the indenter Berkovich (Fig. 1.). Acknowledgments Participation in the conference was financed by the European Union from the European Social Fund by the project POWR.03.05.00-00-Z307/17-00 References [1] A. Mazurkiewicz, J. Smolik: The innovative directions in development and implementations of hybrid technologies in surface engineering. Archives of Metallurgy and Materials 2015, 60(3), 2161–2172. [2] W. Koszela, P. Pawlus, R. Reizer, T. Liskiewicz: The combined effect of surface texturing and DLC coating on the functionalproperties of internal combustion engines. Tribology International 2018, 127, 470–477. [3] F. Cernuschi, P. Bison, D.E. Mack, M. Merlini, S. Boldrini, S. Marchionna, S. Capelli, S. Concari, A. Famengo, A. Moscatelli, W. Stamm: Thermophysical properties of as deposited and aged thermal barrier coatings (TBC) for gas turbines: State-of-the art and advanced TBCs. Journal of the European Ceramic Society 2018, 38(11), 3945–3961. [4] A. Vereschaka, A. Aksenenko, N. Sitnikov, M. Migranov, S. Shevchenko, C. Sotova, A. Batako, N. Andreev: Effect of adhesion and tribological properties of modified composite nano-structured multi-layer nitride coatings on WC-Co tools life. Tribology International 2018, 128, 313–327. [5] S. Makowski, F. Schaller, V. Weihnacht, G. Englberger, M. Becker: Tribochemical induced wear and ultralow friction of superhard ta-C coatings. Wear 2017, 392–393, 139–151. [6] L. Yu, S. Dong, J. Xu, I. Kojima: Microstructure and hardening mechanisms in a-Si3N4/nc-TiN nanostructured multilayers. Thin Solid Films 2008. 516(8), 1864–1870. [7] Zhang S., Z. Wang, P. Guo, P. Ke, M. Odén, A. Wang: Temperature induced superhard CrB2 coatings with preferred (001) orientation deposited by DC magnetron sputtering technique. Surface and Coatings Technology 2017, 322, 134–140. [8] A.D. Pogrebnjak, V.M. Beresnev, K.V. Smyrnova, Y.O. Kravchenko, P.V. Zukowski, G.G. Bondarenko G: The influence of nitrogen pressure on the fabrication of the two-phase superhard nanocomposite (TiZrNbAlYCr)N coatings. Materials Letters 2018, 211, 316–318. [9] M. Rydzewski, J. Kacprzyńska-Gołacka, Z. Słomka, A. Mazurkiewicz, J. Smolik: The impact of magnetron source power on mechanical properties and phase composition of TiB2 coatings. Maintenance Problems 2016, 4, 53–61. [10] R.G. Munro: Material properties of titanium diboride. Journal of Research of the National institute of standards and Technology 2000, 105, 709–720. [11] M. Mikula, B. Grančič, V. Buršíková, A. Csuba, M. Držík, Š. Kavecký, A. Plecenik, P. Kúš: Mechanical properties of superhard TiB2 coatings prepared by DC magnetron sputtering. Vacuum 2007, 82(2), 278–281. [12] M. Rydzewski, J. Kacprzyńska-Gołacka, E. Osuch- -Słomka, M. Kamińska, K. Bilewska, Z. Słomka, J. Smolik, A. Mazurkiewicz: The Impact of Negative Bias Substrate to Fracture Toughness and Hardness of TiB2 Sputtering Coatings. In: 26th International Conference on Metallurgy and Materials, Brno (Czech Republic), May 24th–26th 2017. METAL 2017 Conference Proceedings, 1438–1443. [13] G. Sade, J. Pelleg: Co-sputtered TiB2 as a diffusion barrier for advanced microelectronics with Cu metallization. Applied Surface Science 1995, 9, 263–268.

Resume : III-nitrides are wide bandgap semiconductors mainly used in optoelectronics and high-power electronics. Currently, blue InGaN/GaN light emitters are well-established with efficiencies up to ~80%. However, their efficiency is known to decrease with increasing emission wavelength due to polarization effects and Auger losses. The introduction of In compositional gradient in InGaN/GaN multi quantum wells (MQWs) is expected to reduce these effects, and therefore improve the efficiency of III-nitride emitters.1 Swift heavy ions (SHI) are high energy (above ~1 MeV per nucleon) ions that lose their energy mainly by electronic excitations instead of elastic collisions when passing through the material. Thus, SHI irradiation may be a potential solution to achieve intermixing in MQWs with a reduced density of lattice defects usually generated by low-energy ion irradiation. In this work, the effect of SHI irradiation on the optical properties of InGaN/GaN MQWs is studied. InGaN/GaN MQWs (barrier: 11nm, 5× periods: 13.7 nm) grown by metalorganic vapor phase epitaxy (MOVPE) on GaN on sapphire were irradiated with 92 MeV 129Xe SHI (fluence: 2×1012 cm-2). In order to understand the impact of the ions’ energy on the MQWs, Al foils with different thicknesses were placed in front of the beam to reduce its energy from 80 MeV (Al thickness: 0.8 μm; energy loss at the surface (SES): 21.1 keV/nm) to 36 MeV (Al thickness: 5 μm; SES: 12.6 keV/nm). These values are above and below the reported threshold value for the formation of ion tracks in GaN (~15 keV/nm).2 As a reference, GaN layers grown on sapphire were also irradiated under the same experimental conditions. The samples were studied by optical spectroscopy techniques: transmission, micro-Raman, photoluminescence (PL), and PL excitation (PLE). It is found that Xe SHI irradiation generates crystal damage, evidenced by i) the activation of the GaN phonon density of states (DOS), Figure 1 (a), and ii) a redshifted and less abrupt GaN near band edge response in the transmission spectra. This behaviour is similar in GaN and InGaN/GaN MQWs. Indeed, an absorption band (peak at ~450 nm) is generated after irradiation for both structures. By exciting through this band, no PL emission is obtained for GaN in the studied spectral range, while it is achieved for MQWs. This resonant electronic state, related to InGaN, is also involved in the Raman scattering process, where an increase of the … ratio and the 2LO phonon (InGaN) is observed in Figure 1 (a). Independently on the SHI energy, a green emission is obtained for the MQWs using the excitation at 460 nm as illustrated in Figure 1 (b). Furthermore, it is important to note that the green emission is no more excited through the GaN NBE after the Xe SHI irradiation. In conclusion, Xe SHI irradiation affects both GaN layers and InGaN/GaN MQWs damaging their crystalline structure. However, for MQWs an electronic state involved in the excitation of the green emission is created, showing the possibility to obtain that emission with lower excitation energy after Xe SHI irradiation. Acknowledgments This work was supported by the project NASIB funded by FCT (Portuguese Foundation for Science and Technology) and FEDER (POCI-01-0145-FEDER-028011 and LISBOA-01-0145-FEDER-029666). This work was developed within the scope of the project I3N, UIDB/50025/2020 & UIDP/50025/2020, financed by national funds through the FCT/MEC. J. Cardoso acknowledges the PhD grant DAEPHYS-FCT PD/BD/142780/2018. References [1] K. O’Donnell, M. Auf der Maur, A. Di Carlo, K. Lorenz, and the SORBET consortium, Physica Status Solidi – Rapid Research Letters 2012, 6, 49-52 [2] F. Moisy, C. Grygiel, A. Ribet, M. Sall, E. Balanzat, and I. Monnet, Nuclear Instruments and Methods in Physics Research B 2016, 379, 246-250

Resume : Materials used at high temperature often require good mechanical properties (e.g., fracture toughness, bending strength, etc.), good resistance to thermal shock, creep resistance, high thermal conductivity, good tribological and wear properties [1-4]. Ceramic materials have been extensively investigated in previous decades due to their high temperature performance in general. As one of the most promising candidates of structural ceramics, silicon nitride (Si3N4) meets the requirements mentioned above (e.g., low coefficient of thermal expansion (CTE), good thermal conductivity and high strength results in a higher thermal shock resistance than most other ceramic materials). Therefore it is commonly used in a variety of structural applications such as cutting tools, pump seal parts, bearing balls, gas turbine engine parts or heat exchangers [5-7]. Typical metal oxides (e.g., MgO, Al2O3, Y2O3, or ZrO2) in Si3N4 promote a liquid phase formation, which facilitates the consolidation [4]. Due to the unique combination of electrical, thermal and mechanical properties [8], graphene and graphene oxide (GO) have been considered as filling component in ceramic composites in the last decade. Although using either ZrO2 or graphene nanofiller to improve the properties of Si3N4 has been reported, the study on the combined effect by both is rather rare. Silicon nitride-zirconia-graphene composites with high graphene content (5 wt% and 30 wt%) were sintered by gas pressure sintering (GPS) in this study. The effect of multilayer graphene (MLG) content on microstructure is investigated by multi-scale microscopy. Multi-scale microscopy confirms that the phases disperse evenly in the microstructure without obvious agglomeration. The size distribution of Si3N4 phase shifts towards a larger size range with the increase of graphene content from 5 wt% to 30 wt%, while a higher graphene content (30 wt%) hinders the growth of ZrO2 phase. MLG flakes well dispersed between ceramic matrix grains can slow down the phase transformation from α to β-Si3N4, subsequent needle like growth of β-Si3N4 rods and the densification due to the reduction of the sintering additives particularly in the case with 30 wt% MLG. Since MLG fillers in Si3N4- ZrO2 ceramics makes the densification of composites more difficult, high porosity up to 50% is observed. Highly heterogeneous ceramic composite with shear-weak graphene and high porosity results in considerable redistribution of stresses under indentation. This type of dispersed damage caused by significant redistributed stresses prevents the formation of long macro cracks (classical radial cracks), which often occur in homogenous Si3N4 ceramic. Therefore, both of the Si3N4/MLG composites show resistance to contact or indentation damage. Figure 1 shows two extracted slices from a volumetric reconstruction of X-ray computed tomography data. The square pillar sample was prepared from the synthesized composite with 30 wt% MLG using focused ion beam (FIB) milling in a scanning electron microscope. The 3D microstructure study using X-ray microscopy (XRM) was performed at synchrotron source (BESSY II, U41-PGM1-XM beamline [9]). ZrO2 phases could be easily differentiated by the contrast, while only partial Si3N4 phases could be distinguished from mixed Si3N4 phase and MLG flakes. The phases are dispersed homogenously in the 3D microstructure, no obvious agglomeration of phases was observed.

Resume : Zinc oxide (ZnO) is one of the mostcommon transparent conductive oxide (TCO), havingunique properties, such as wide band gap of 3.37 eV, high electrical conductivity (~102 Ω-1·cm-1), large binding energy (60meV), combined with high charge carrier mobility. This is why it has found wide application in different fields, mainly in microelectronics, including gas sensor devices, photodiodes, flat-panel displays,and solar cells [1- 4].Moreover, ZnO – in the form of low dimensional nanostructures – exhibits an interesting photocatalytic activity, which can be applied in the effective UV-light activated photocatalytic degradation of different types of dyes – such as methylene blue (MB) –in the process of water purification[5,6]. In this work, the ability of ZnO nanostructures to photocatalytically degrade MB in aqueous solution was investigated: these nanostructured ZnO porous thin films were deposited by direct current reactive sputtering (DCRS)on the Si substrates [7-9]. To study the mechanism of MB photocatalytic degradation in depth, surface morphology and surface chemistry of these nanostructured ZnO porous thin films were assessed using complementary techniquessuch asAtomic Force Microscopy (AFM) and X-ray Photoelectron Spectroscopy (XPS). The photodegradation of MB was performed illuminating the samples with an irradiance of ~ 2.0 mWcm-2. The degradation reaction (removal) of MB in aqueous solution upon UV irradiation was followed by spectrophotometric measurements. The observed absorption decay followed a zero-order kinetics [10] and was fitted using the following equation: [𝐴]! = −𝑘 ∙ 𝑡 + [𝐴]" where [A]t is the concentration of MB at irradiation time t, [A]0the initial concentration of MB, k the zero-order rate constant, and t their radiation time. This kinetic behaviour is typical of degradation occurring with immobilised photocatalysts. The obtained results were interpreted on the basis of the information on the surface properties and the relevant photocatalytic properties of ZnO nanostructured porous thin films: their surface morphology was studied together with the surface chemistry, which revealedtheadsorption of various undesired gases present in the atmosphere and other contaminants dissolved inwater, as determined by using XPS and AFM methods. Finally, our studies confirmed that properly selected ZnO nanostructures can be very efficient for the photocatalytic degradation of MB in water purification, whichpaves the way for the utilization of these nanomaterials for environmental remediation purposes. Acknowledgments The work has been realized within the national budgetary sources on science of the Faculty of Automatic Control, Electronics and Computer Science, Department of Cybernetics, Nanotechnology and Data Processing, Silesian University of Technology, Gliwice, Poland. The photodegradation experiments and the relevant data analysis were performed at the Chair of Materials Science and Nanotechnology at Dresden University of Technology, Germany. The research of M.K. and A.K.K. was funded by the National Science Centre in Poland granted according to decisions DEC-2016/21/B/ST7/02244. References [1] Ch.Jagadish, S.Pearton, Zinc Oxide: Bulk, Thin Films and Nanostructures, Elsevier: Amsterdam, 2006. [2] K.Elmer, A.Klein, B.Rech, Transparent Conductive Zinc Oxide – Basics and Application in Thin Films Solar Cells, Springer: Berlin, 2007. [3] Q.Zhang, C.S.Dandeneau, X.Zhou,G.Cao, ZnO nanostructures for dye sensitized solar cells, Adv.Mater. 21 (2009)4087–4108. [4] M.A.Carpenter, S.Mathur, A.Kolmakov, Metal oxide nanomaterials for chemical sensors, Springer: New York, 2012. [5] S.H.Sh.Chan, T.Y.Wu, J.Ch.Juan, Ch.Y.Teh, Recent developments of metal oxide semiconductors as photocatalysts in advanced oxidation processes (AOPs) for treatment of dye waste‐water, J.Chem.Technol.Biotechnol. 86 (2011) 1130–1158. [6] A.Pandikumar, K.Jothivenkatachalam (Editor’s), Photocatalytic Functional Materials for Environmental Remediation, John Wiley & Sons Inc., 2019. [7] M.A.Borysiewicz, E.Dynowska, V.Kolkovsky, J.Dyczewski, M.Wielgus, E.Kaminska, A.Piotrowska, From porous to dense thin ZnO films through reactive DC sputter deposition onto Si(100) substrates,Phys. Status Solidi A 12 (2012), 2463–2469. [8] M.Masłyk, M.A.Borysiewicz, M.Wzorek,T.Wojciechowski, M.Kwoka, E.Kaminska, Influence of absolute argon and oxygen flow values at a constant ratio on the growth of Zn/ZnO nanostructures obtained by DC reactive magnetron sputtering,Appl. Surf. Sci. 389 (2016) 287–293. [9] M. Kwoka, B. Lyson-Sypien, A. Kulis, M. Maslyk, M.A. Borysiewicz, L. Kaminska, J. Szuber, Surface properties of nanostructured porous ZnO thin films prepared by direct current reactive magnetron sputtering, Materials 11 (2018) 131. [10] H. Zhang, D. Liu, S. Ren, H. Zhang,Kinetic studies of direct blue photodegradation over flower-like TiO2 . Res. Chem.Intermed. 43(2017), 1529–1542.

Resume : A number of oxide ceramic materials such as alumina, titanium, tin, and zirconium dioxides and others are widely used as refractories, sensitive elements of sensors, catalysts, photocatalysts in dye-sensitized solar cells and water treatment. Due to the unique properties of nanofibers, such as high surface-area-to-volume ratio, porosity, mechanical strength, these materials in nanofibrous form show better characteristics and are used in advanced composite materials. The presented work aims to study the application potential of the solution-based needle-less electrospinning, performed on the Nanospider NS Lab200 machine, as a perspective technique for nanofibrous materials preparation. The main focus of the study was made on the preparation of the precursor fibrous materials and its transformation into special ceramic ones. This was performed based on a titanium dioxide (TiO2) system. The fabrication process consisted of three basic steps: 1) preparation of spinning solution; 2) electrospinning; 3) postspinning treatment. For spinning solutions preparation polyvinylpyrrolidone (PVP), titanium tetraisopropoxide, ethanol, and acetic acid were used. Prepared precursor fibers were used to study the influence of the postspinning treatment type - conventional heat or low-temperature plasma treatment, and its conditions on the composition, morphology, and properties of the final fibrous materials, obtained from the same precursor fibers. The post-spinning treatment is the key step for the transformation of electrospun precursor fibers to oxide or non-oxide ceramic, carbon, and polymer-based composite fibrous materials. Titanium dioxide was chosen due to the multifunctional nature and possibility of simple transformation into nonoxide ceramics, which allows being used further as the model system for the preparation and study of fibrous ultra-high temperature ceramics. As a result (Figure 1), after the calcination of the electrospun precursor in air, a series of titanium oxide nano/microfibers with different anatase to rutile phase ratio was obtained. In the case of the heat treatment experiments in the inert argon atmosphere – the carbothermal reduction took place and composite carbon/titanium oxides and titanium carbide fibers were obtained [1]. The same electrospun precursor fibers were treated by low-temperature plasma-induced surface sintering process by a special dielectric barrier discharge, so-called, Diffuse Coplanar Surface Barrier Discharge (DCSBD). Plasma treatment of the prepared samples was performed in three different by nature atmospheres: oxidative – air, reductive – H2, and inert – N2. The exposure times were 10, 30, and 60 min at the input power of 400 W. Impact of the plasma treatment time in different atmospheres on the morphology and chemical composition of the PVP/TiO2 microfiber mats was studied. This type of treatment led to the formation of flexible composite TiO2/PVP core/shell fibers. It was found that a thin ceramic layer was formed on the surface of the fibers, thickness, and morphology of which depends directly on the exposure time and atmosphere. One of the main aims of this work was to compare the impact of plasma treatment in the atmosphere with different chemical nature on the same composite system [2]. For the comprehensive structural and chemical study of the prepared materials electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM/EDS, TEM), differential thermal analysis, differential scanning calorimetry coupled with thermogravimetry (DTA, DSC/TG), X-ray diffraction (XRD), and small-angle X-ray scattering (SAXS), ultraviolet-visible (UV-Vis), Fourier-transform infrared (FTIR), Raman, and X-ray photoelectron (XPS) spectroscopies were used. Acknowledgments This work was supported by the Scientific Grant Agency of the Ministry of Education, Science, Research and Sport of the Slovak Republic and the Slovak Academy of Sciences, project No. VEGA 2/0099/18, Slovak Research and Development Agency under the contract No. APVV-15-0469, APVV-19-0625 the project „Research Centre of Advanced Materials and Technologies for Recent and Future Applications "PROMATECH", ITMS 26220220186, supported by the Operational Program "Research and Development" financed through the European Regional Development Fund, and the project LO1411 (NPU I) funded by Ministry of Education Youth and Sports of Czech Republic. References [1] I. Shepa, E. Mudra, M. Vojtko, P. Tatarko, V. Girman, O. Milkovic, T. Sopcak, V. Medvecka, J. Dusza, Ceramics International 2018, 44, 17925. [2] I. Shepa, E. Mudra, D. Pavlinak, V. Antal, J. Bednarcik, O. Mikovic, A. Kovalcikova, J. Dusza, Applied Surface Science 2020, 523, 146381.

Resume : Diatoms are the largest and the ecologically most significant group of organisms on Earth. Due to the unique silicified cell structure as well as intricate morphology, these microorganisms attract scientists attention for a long time. Nevertheless, discussions about the details of their structure as well as functionalities, between scientists from various science fields, are still ongoing. Nowadays, possible applications of these diatoms shells are the subject of many works. The variety of the species makes it possible to choose frustule with desired structure, size as well as other parameters. One of the species of Authors’ interest is freshwater diatom – Didymosphenia geminata. In addition to siliceous cells, Didymosphenia geminata secretes extracellular polymeric fibrous material in form of stalks. These stalks are responsible for attachment to substrates, like stones, plants, debris. The current studies allowed to conduct several investigations which allow to obtain comprehensive information’s about siliceous shells. In addition to that, preliminary results of the possibilities of using frustules of this diatoms as a novel filler in epoxy composites have been presented in [1,2]. Acknowledgments Izabela Zglobicka acknowledges funding provided by German Academic Exchange Service (DAAD) within Research Grants – Short–Term Grants 2017 (ID: 57314023) and National Science Center for providing financial support to project Metal Matrix Composites with natural filler (Grant No. 2018/31/D/ST8/00890). References [1] Zglobicka I., Li Q., Gluch J., Plocinska M., Noga T., Dobosz R., Szoszkiewicz R., Witkowski A., Zschech E., Kurzydlowski K.J. (2017): Visualtization of the internal structure of Didymosphenia geminate frustules using nano X-ray tomography. Scientific Reports, 7, 9086. DOI: 10.1038/s41598-017-08960-5 [2] Zglobicka I., Jablonska J., Suchecki P., Mazurkiewicz-Pawlicka M., Jaroszewicz J., Jastrzebska A., Pakiela Z., Lewandowska M., Swieszkowski W., Witkowski A., Kurzydlowski K.J. (2018) : Frustules of Didymosphenia geminata as a modifier of resins. Inzynieria Materialowa, 5(225): 172-177. DOI: 10.15199/28.2018.5.2

Resume : In this work, a novel approach is presented to identify and evaluate the occurring damage in BEoL (Back End of Line) stacks under mechanical load. The measurement strategy is firstly applied to evaluate the mechanical stability in the BEoL stack of copper (Cu) pillar bumped chips manufactured in 28 nm technology. In the measurement workflow, shear force is applied to a single Cu-pillar utilizing a tribo indenter system with a customized tip. The sample is placed in a special sample holder directly on top of a piezo-based acoustic emission (AE) sensor. While shearing off the pillar, acoustic signals are measured which are caused by damage events inside the BEoL stack and can be used to determine the exact moment and evaluate the type of damage. The results of the acoustic emission measurements are a valuable additional information to the mechanical data generated by the tribo indenter system. In combination with the damage visualization by e.g. light microscopy, it provides a more holistic insight to the damage infliction and propagation process in the BEoL stack and enables the identification of critical damage prone areas. Keywords - Back End of Line stack stability; Chip Package Interaction; Acoustic Emission, Cu-Pillar Shear-Off, Advanced Packaging

Resume : X-rays are essential in a wide variety of advanced characterisation techniques to probe properties of matter. However, interactions of X-rays with crystalline matter are known to induce a range of changes. Despite the undesirable consequences of radiation being well documented in biological macromolecular crystallography since it was first studied in the 1960s[1,2], knowledge of the effect of this ionising radiation on small molecular crystals, which are integral in catalytic applications for instance, remains incredibly limited. In recent years the advent of modern microfocused laboratory sources and the shift towards higher brilliance synchrotron sources has exacerbated the problem of unwanted radiation effects, increasing the necessity for a better understanding of its influence on matter. The main aims of observing changes caused by irradiation are not only to design and implement preventative measures but also to fully understand the radiation damage process and how it occurs in the materials being studied. In this study, a combined approach of synchrotron (Diamond Light Source) powder X-ray diffraction (XRD) with X-ray Photoelectron Spectroscopy (XPS) is implemented to infer changes to the structure and to the local chemical environments, as well as changes to the electronic structure of a family of prototypical catalysts. These have the general formula [M(COD)X]2 where M= Ir, Rh, COD= cyclooctadiene and X= Cl. Approaching radiation effects with this combination of advanced techniques allows for a compelling, novel multi-modal way to probe effects of X-ray irradiation, by way of a direct correlation of structural changes with changes of the chemical state of the metal. The progression of radiation-induced changes to these small molecular crystals is monitored over considerable timescales and observations from experiments are complemented with theoretical results from Density Functional Theory (DFT) calculations. Insights into the structural implications of probing the sample at the high resolution I11 PXRD beamline at Diamond Light Source are obtained from Le Bail refinements. In addition, the X-ray induced effects relative to absorbed radiation dose will be discussed. These values of X-ray dose are obtained using a recent development in the RADDOSE-3D utility[3] for radiation dose estimation in small molecular systems.[4] The changes observed in the behaviour of the different catalyst materials within this transition metal-chloride-complex family will be presented with respect to structure and chemical properties. This work thus presents an insight into the stability of these industrially significant materials and opens the path for promising future work in damage mitigation strategies, made important by the development of new generation X-ray sources. References [1] C. Blake and D. Philips, Symposium of the International Atomic Energy Agency, 1962, 183. [2] E. F. Garman, Acta Crystallogr., Sect. D, 2010, 66, 339–351 [3] C.S. Bury et al., Protein Sci., 2018, 27, 217-228 [4] J. Christensen et al., IUCrJ, 2019, 6, 703-713

Resume : tba

Resume : Modern material science, chemistry and biochemistry work with more and more complex materials and synthetic routes that often do not yield large single crystals. If the maximum available crystal size reaches only a few hundred nanometres or even less, the only practically feasible approach to single crystal structure analysis is the application of electron diffraction. Single crystal structure analysis by electron diffraction faces a number of fundamental as well as technical problems. However, many of these problems have been at least partly solved in the past few years, and the fast development of the method has received a lot of attention and positive reception in the crystallographic and materials-science community. At present, three-dimensional electron diffraction (3D ED) methods are being used in many laboratories almost routinely to analyze the crystal structures of a wide variety of materials, ranging from metals, oxides and other inorganic materials through minerals, framework and porous materials to organic molecular crystals and macromolecular crystals [1]. The lecture will briefly review the basics and history of the 3D ED methods and illustrate its potential on three selected examples – semiconducting tantalum trisulphide, structure determination of a new phase in the Ni-Ti system and analysis of carbon-dioxide adsorption in nanocrystalline zeolite. 1. M. Gemmi, E. Mugnaioli, T. E. Gorelik, U. Kolb, L. Palatinus, P. Boullay, S. Hovmöller, J. P. Abrahams (2019): 3D electron diffraction: the nanocrystallography revolution. ACS Cent. Sci. 5, 1315-1329.

Resume : Nowadays, many new ways of storing as well as transmitting electricity are heavily researched. Although there are already many battery systems, lithium batteries are currently finding more and more applications on the consumer market [1]. Thermodynamic properties, phase equilibria and phase transitions are data of crucial importance when developing electrodes for batteries. Tools used for this process are different types of thermodynamic bases, containing the necessary information. However not all systems have been tested experimentally, therefore thermodynamic databases need to be constantly updated. In this work we propose liquid alloys from Ga-In-Li and Ga-Ge-Li systems as electrode materials for liquid metal batteries. A schematic illustration of such device is presented in Fig.1. There is a lack of thermodynamic data in the literature on these two systems, which results in the need to conduct experimental studies of the above-mentioned systems in order to obtain the necessary data. The two selected ternary systems consist of 5 two-component systems: Ga-Li [3], Ga-In [4] In-Li [5], Ge-Li [6] Ge-Ga [7]. Electromotive and calorimetric tests were carried out in the selected systems. This work presents thermodynamic information about the Ga-In-Li and Ga-Ge-Li phase diagram. Moreover electromotive force measurements were conducted for the mentioned systems. The cells were prepared using a glovebox chamber with protective argon atmosphere. Eutectic KCl-LiCl and LiF-LiCl salts were used in the preparation of the electrolyte. The construction of the cell is shown in Fig 2. The obtained results will be used to optimize the thermodynamic properties of the phases present in the ternary Ga-In-Li and Ga-Ge-Li system, and for calculation of the phase diagrams of binary and ternary systems. Acknowledgements The research was co-financed by the European Union from resources of the European Social Fund (Project No.WNDPOWR.03.02.00-00-I043/16). References [1] K. Wang, K. Jiang, B. Chung, T. Ouchi, P. J. Burke, D. A. Boysen, D. J. Bradwell, H. Kim, U. Muecke i D. R. Sadoway, Nature, 348-350, 2014. [2] Scrosati, Bruno, and Jürgen Garche. J. Power Sources 195.9, 2419-2430, 2010. [3] H. Azza, N. Selhaoui, A. Iddaoudi, L. Bouirden, J. Phase Equilib. Diffus. 12,2,1991. [4] T.J. Anderson, I. Ansara, J. Phase Equilib. Diffus. 12,1,1991. [5] H. Okamoto, J. Phase Equilib. Diffus.27,2, 2006. [6] S. Wang, Y. Du, Y. Peng, P. Zhou, X. Yuan, S. Liu, J. Phase Equilib. Diffus. 39, 315-323, 2018. [7] R. W. Olesinski G. J. Abbaschian, J. Phase Equilib. Diffus., 6, 258-262, 1985.

Resume : Energy sector is a driving force for development of economic countries [1]. Nonetheless the main energy sources all over the world are fossil fuels like coal, nature gas and oil, which usage leads to the formation of for example NOx, SO2 and CO2. The global movement is focused on the reduction of emission greenhouse gases [2]. This brings us to the point where energy sector must use energy sources that are both ecological and economical. One of the options which meet these requirements is thermal conversion of biomass. The pyrolysis seems to be promising one, this process occurs in temperature range from 300 °C up to 700 °C in anaerobic environment. It is leading to production solid (biochar), liquid (biooil) and gaseous products with different efficiency depending on process parameters [3, 4]. This paper is focused on the catalytic pyrolysis. The main aim of the application of catalysts is to improve the quality of products compared to normal pyrolysis. Well-known catalysts such as Ni, Mg or Fe promote production of hydrogen via methane reformation [5], as well as parallel reforming of hydrocarbons contained in the material and CO2 capture [6]. The catalyst can be applied, thus: i). in situ catalytic pyrolysis (the catalyst and the biomass feedstock are mixed in the pyrolysis reactor and the action happens within the same reactor) and ii). ex situ catalytic pyrolysis (the catalysts are placed in a separate reactor for catalytic upgrading of pyrolysis vapours). The catalyst should be characterised by appropriate properties such as specific surface area, micropore area, pore size distribution, framework structure, crystalline phase and crystallite size, and availability. The most often studied basic catalysts in pyrolysis are based on CaO and MgO: Ni-Mg-Al-CaO, Ni-Mg-Al-Ca and Ni-CaO-C [7, 8]. They are dedicated for fast pyrolysis considering their excellent deacidification, resulting in a lower acidity and a higher heating value of bio-oil [9]. To upgrade bio-oil from pyrolysis, various types of zeolites (ZSM-5, Y zeolite, MCM- 41 zeolite, β-zeolite, and novel zeolite) [10] and solid acid (SiO2, Al2O3, Al2O3-SiO2) [11] materials are also extensively investigated. Moreover, transition metal oxides (TiO, NiO, ZnO, ZrO2, CuO, CeO2 and MnO2) have been employed in supporting catalysts to prepare heterogeneous catalysts [12, 13]. Hydrocarbon-rich products and pure oil is preferable as the final product of the process. Thus, the multi-functional catalysts are required for enhancing bio-oil quality by promoting hydrogen transfer and depolymerisation. Acknowledgments: This work was realized as a part of fundamental research financed by AGH University of Science and Technology [Grant No 16.16.110.663]. References [1] K. Zaman and M.A. el Moemen, Energy consumption, carbon dioxide emissions and economic development: Evaluating alternative and plausible environmental hypothesis for sustainable growth., Renewable and Sustainable Energy Reviews. vol. 74, pp. 1119–1130, 2017. [2] M. Mujuru, T. Dube, H. Mabizela, and N. Ntuli, Evaluating greenhouse gas emission reductions by using solar water heaters: A case of low income households in Ekurhuleni, South Africa., Physics and Chemistry of the Earth. vol. 116, p. 2020. [3] M. Sieradzka, N. Gao, C. Quan, A. Mlonka-Mędrala, and A. Magdziarz, Biomass thermochemical conversion via pyrolysis with integrated CO2 capture., Energies. vol. 13, no. 5, p. 1050, 2020. [4] A. Mlonka-Mędrala, A. Magdziarz, T. Dziok, M. Sieradzka, and W. Nowak, Laboratory studies on the influence of biomass particle size on pyrolysis and combustion using TG GC/MS., Fuel. vol. 252, pp. 635–645, 2019. [5] G. Liu, Y. Liao, Y. Wu, and X. Ma, Synthesis gas production from microalgae gasification in the presence of Fe2O3 oxygen carrier and CaO additive., Applied Energy. vol. 212, pp. 955–965, 2018. [6] C. Wu and P.T. Williams, A novel Ni-Mg-Al-CaO catalyst with the dual functions of catalysis and CO2 sorption for H2 production from the pyrolysis-gasification of polypropylene., Fuel. vol. 89, no. 7, pp. 1435–1441, 2010. [7] S. Kumagai, J. Alvarez, P.H. Blanco, et al., Novel Ni-Mg-Al-Ca catalyst for enhanced hydrogen production for the pyrolysis-gasification of a biomass/plastic mixture., Journal of Analytical and Applied Pyrolysis. vol. 113, pp. 15–21, 2015. [8] L. Sun, X. Zhang, L. Chen, B. Zhao, S. Yang, and X. Xie, Effects of Fe contents on fast pyrolysis of biomass with Fe/CaO catalysts., Journal of Analytical and Applied Pyrolysis. vol. 119, pp. 133–138, 2016. [9] P. Sudarsanam, E. Peeters, E. V. Makshina, V.I. Parvulescu, and B.F. Sels, Advances in porous and nanoscale catalysts for viable biomass conversion., Chemical Society Reviews. vol. 48, no. 8, pp. 2366–2421, 2019. [10] M. Sharifzadeh, M. Sadeqzadeh, M. Guo, et al., The multi-scale challenges of biomass fast pyrolysis and bio-oil upgrading: Review of the state of art and future research directions., Progress in Energy and Combustion Science. vol. 71, pp. 1–80, 2019. [11] Y.L. Tan, A.Z. Abdullah, and B.H. Hameed, Catalytic fast pyrolysis of durian rind using silica-alumina catalyst: Effects of pyrolysis parameters., Bioresource Technology. vol. 264, pp. 198–205, 2018. [12] S. Yang, F. Zhou, Y. Liu, et al., Morphology effect of ceria on the performance of CuO/CeO 2 catalysts for hydrogen production by methanol steam reforming., International Journal of Hydrogen Energy. vol. 44, no. 14, pp. 7252–7261, 2019. [13] N. Gao, Y. Han, C. Quan, and C. Wu, Promoting hydrogen-rich syngas production from catalytic reforming of biomass pyrolysis oil on nanosized nickel-ceramic catalysts., Applied Thermal Engineering. vol. 125, pp. 297–305, 2017.

Resume : In recent years with the evolution of modern society, new and emergent technologies, such as flexible and wearable electronics, have been improving the overall well-being and human quality of life [1]. The great challenge of many researchers around the world is to continue pushing technology barriers further, exploiting the full potential of new smart devices and improving the already developed[2]. Toward devices that can be introduced in the future, it is necessary to have advanced sensors with high efficiency, light-weight, flexibility, durability, low-power consumption, biocompatibility, conformable properties and reproductible large-area manufacturing processes [3]. The flexible electronics family has been increasingly growing integrating high performance sensors, capacitors, light-emitting diodes, RFID antennas and so on[1]. Furthermore, flexible electronics can offer a novel range of applications, such as biological and environmental monitoring, energy harvesting and storage, intelligent robotics, electronic paper, smart clothing, flexible displays, healthcare sensors, and much more [4]. Over the past decade, various materials have received tremendous attention, as carbon materials, including graphite, active carbon, carbon nanotubes or graphene have focused most of the interest [5]. These present unique and advantageous properties such as excellent conductivity, thermal and chemical stability, high strength and outstanding flexibility. Also, these could be easily functionalized, giving them great features to be integrated as sensors as well as storage devices for various smart wearable devices [6]. Graphene is the one that stands out from this family of carbon materials, a one-atom thick layer of graphite arranged in a honeycomb lattice [7, 8]. As mentioned, it is essential to select and develop proper materials to be mass-produced in a reproducible, ecofriendly, and inexpensive fabrication process [1]. Currently, the graphene fabrication and patterning processes are mostly based on screen-printing, stamp-imprinting, inkjet-printing, slow-flow assisted assembly, photolithography, chemical etching and vacuum coating technology. Those conventional techniques generally require additional steps to improve specific proprieties on substrates increasing fabrication complexity, are expensive and time consuming which highlights the need to find sustainable alternatives [7, 9]. An alternative has been explored and appears to be one of the most promising approach (Figure 1). By using a laser-direct writing with a CO2 infrared laser, a one-step fabrication process is possible to prepare laser-induced graphene (LIG) under air conditions [10]. With this method, laser is focused to heat a specific zone and converts (photothermally) sp3 hybridized carbon atoms, found in substrates, into sp2 hybridized carbon - the carbon allotrope found in graphene [1, 10]. Laser generates a confined temperature field at a desired position with high controllability to produce a three-dimensional material. LIG has a superhydrophobic structure and could be doped with metal oxide nanocrystals, functionalized with polymers, or developed into vertically-aligned graphene fibers [10, 11]. The peculiarity of the LIG lies in its versatility, manipulating endless promising carbon materials as well enabling a cost breakthrough and a rapid production of conductive patterns that can be structured designed in robust, thin, and conformable devices. Finally, the challenge and future perspectives of this work is creating a next-generation of flexible electronics toward the development of sensors and supercapacitors using a single low-cost fabrication process, and posteriorly be applied in smart wearable systems [4, 12]. Acknowledgments The authors acknowledge financial support from Projects No. H2020 - ERC-2017-ADG, and No. UID/Multi/04378/2013. Sara Silvestre acknowledge PhD Grant SFRH/BD/115173/2016, respectively. References [1] Y. Huang, X. Fan, S. C. Chen, and N. Zhao, “Emerging Technologies of Flexible Pressure Sensors: Materials, Modeling, Devices, and Manufacturing,” Adv. Funct. Mater., vol. 1808509, pp. 1–24, 2019, doi: 10.1002/adfm.201808509. [2] H. Kim and J. H. Ahn, “Graphene for flexible and wearable device applications,” Carbon N. Y., vol. 120, pp. 244–257, 2017, doi: 10.1016/j.carbon.2017.05.041. [3] Z. Luo et al., “Structure-Property Relationships in Graphene-Based Strain and Pressure Sensors for Potential Artificial Intelligence Applications,” Sensors, vol. 19, no. 5, p. 1250, 2019, doi: 10.3390/s19051250. [4] A. Samouco, A. C. Marques, A. Pimentel, R. Martins, and E. Fortunato, “Laser-induced electrodes towards low-cost flexible UV ZnO sensors,” Flex. Print. Electron., vol. 3, no. 4, pp. 0–21, 2018, doi: 10.1088/2058- 8585/aaed77. [5] L. X. Duy, Z. Peng, Y. Li, J. Zhang, Y. Ji, and J. M. Tour, “Laser-induced graphene fibers,” Carbon N. Y., vol. 126, pp. 472–479, 2018, doi: 10.1016/j.carbon.2017.10.036. [6] C. Wang, K. Xia, H. Wang, X. Liang, Z. Yin, and Y. Zhang, “Advanced Carbon for Flexible and Wearable Electronics,” Adv. Mater., vol. 1801072, pp. 1–37, 2018, doi: 10.1002/adma.201801072. [7] J. Zhu, X. Guo, H. Wang, and W. Song, “Cost-effective fabrication and high-frequency response of nonideal RC application based on 3D porous laser-induced graphene,” J. Mater. Sci., vol. 53, no. 17, pp. 12413–12420, 2018, doi: 10.1007/s10853-018-2514-y. [8] F. Wang et al., “Laser-induced graphene: preparation, functionalization and applications,” Mater. Technol., vol. 33, no. 5, pp. 340–356, 2018, doi: 10.1080/10667857.2018.1447265. [9] T. Hou, S. Bai, W. Zhou, and A. Hu, “Laser directwriting of highly conductive circuits on modified polyimide,” J. Laser Micro Nanoeng., vol. 12, no. 1, pp. 10–15, 2017, doi: 10.2961/jlmn.2017.01.0003. [10] N. T. Garland et al., “Flexible Laser-Induced Graphene for Nitrogen Sensing in Soil,” ACS Appl. Mater. Interfaces, vol. 10, no. 45, pp. 39124–39133, 2018, doi: 10.1021/acsami.8b10991. [11] R. Ye et al., “Laser-Induced Graphene Formation on Wood,” Adv. Mater., vol. 29, no. 37, p. 1702211, Oct. 2017, doi: 10.1002/adma.201702211. [12] A. Lamberti, F. Clerici, M. Fontana, and L. Scaltrito, “A highly stretchable supercapacitor using laserinduced graphene electrodes onto elastomeric substrate,” Adv. Energy Mater., vol. 6, no. 10, pp. 1–6, 2016, doi: 10.1002/aenm.201600050.

Resume : Organic flexible electronics have received considerable attention in sensing, displaying, diagnosing, memorizing [1], with the possibility of low cost, ultralight weight, mechanical bendability and versatile chemical design. Among current materials for device fabrication, novel two-dimensional polymers (2DPs) are most promising due to their intrinsic structural stretchability, tuneable electronic properties including bandgap and conductivity, and considerable carrier mobility [2]. However, the practical feasibility of introducing novel 2DPs into flexible devices requires the premise with deep understanding of how the mechanical deformation affects their microstructure and properties. Here, we demonstrate TEM results for several novel 2DPs (including 2D polyimine and 2D hexaaminobenzene-Cu (HAB-Cu) for transistor device, q2D polyaniline for sensor device because of their great abilities of large-area synthesis and high crystallinity). TEM and high-resolution TEM were performed to image the crystallinity and molecular structures. The maximum degree of crystallinity ensures satisfied long-range carrier transport properties. TEM images are shown in Fig.1, 2D polyimine and 2D HAB-Cu exhibit high distribution of crystals and clear lattices, which reveals great ability of crystalline with assistance of surfactant in the interface between air and water. The domains can grow up to 150 nm and 50 nm, respectively. Electron energy loss spectroscopy (EELS) was used to verify its possibility of characterizing the changes of chemical bonds in 2DPs. Since electron beam is not stable and may cause drift and value jumping during the recording process, it is of great importance to firstly figure out whether EELS data is reliable and accurate enough. Additionally, the zero-loss peak (ZLP) is undetectable when the core loss peak is requiring, therefore we assumed that dynamic carbon Kedge peak instead of ZLP as a reference peak to quantitatively determine the movement of peaks to eliminate the effect of drift would be meaningful. The EELS spectra of two kinds of 2D coordination polymers (CuNi(CN)4 and CuPt(CN)4) are shown in Fig.2. The core-edge loss intensities of two curves vary from each other due their different relative specimen thicknesses (tR) under the same illumination step [3]. The EELS spectra show the carbon and nitrogen K-edge peaks of 2DPs and they deviate from standard peak values, which may be caused by drift. The peaks of energy loss can be assigned to 1s-π* transition indicating the functional group of C≡N [4]. The energy gap of relative difference between carbon and nitrogen peaks is identical to the gap between respective carbon and nitrogen peak of CuNi(CN)4 and CuPt(CN)4. This means values of different core-loss peaks change synchronously. After ensuring that there will be a same change between ZLP and carbon K-edge peaks could verify the feasibility of EELS. We are planning to use an in-situ push-to-pull manipulator in TEM as a tool to observe the mechanical behavior and failure process of 2DPs at molecular level. Acknowledgments B. Zhang thanks the financial support from China Scholarship Council (CSC). We also gratefully acknowledge SangWook Park, Wei Li and Peng Zhang from the Faculty of Chemistry and Food Chemistry, Technische Universität Dresden for providing novel two-dimensional polymer samples, and Luis Antonio Panes Ruiz from Institute for Materials Science, Technische Universität Dresden for sensor device fabrication and test. References [1] Wang, C., Huang, Z., Xu, S, Advanced Materials, 2018, 30(50), 1801368. [2] Feng, X., Schlüter, A. D, Angewandte Chemie International Edition, 2018, 57(42), 13748-13763. [3] Hosoi, J, et al. Ultramicroscopy, 1984, 13(3), 329-332. [4] Cody, et al. Meteoritics & Planetary Science, 2008, 43(1-2), 353-365.

Resume : Metal organic frameworks (MOFs) are hybrid materials that consist of organic ligands and metal ions or clusters. Recently, increasing number of MOFs have been recognized for a great potential in CO2 capture due to their high surface area. Especially, HKUST-1 consisted of copper nodes and organic ligands is one of the most widely studied MOFs owing to its high porosity. In this work, we synthesized HKUST-1 in the lumen of modified Halloysite clay nanotubes (mHNTs). Here, HNT acted as a nanocarrier to load precursor solution of HKUST-1 inside and nano-size HKUST-1 was successfully synthesized in this limited cage. Furthermore, HNTs helped to protect HKUST-1 from water exposure. Experimentally, inner or outer surface of HNTs were selectively modified with sulfuric acid and (3-Aminopropyl)triethoxysilane. Each mHNT was designated EHNT and HNT-NH2. Then, HKUST-1 precursor was evenly loaded into the lumen of HNTs in a solution phase, and the crystalline MOFs were syntehsized via solvothermal method. The final procuct was named to EHNT@HKUST-1, HNT-NH2@HKUST-1 respectively. As nanocarriers, HNTs provided confining spaces to make specific boundary for growing MOFs with longitudinal axis of HNTs and improved water stabililty of MOFs. Also, selectively modified HNTs imparted unique properties to the surface of composites. Specifically, ething treatment through sulfuric acid provided effective method for expansion of lumen in HNTs and made it possible to maximize the loading of the precursor solution. Amine functionalization, meanwhile, granted more enhanced CO2 gas adsorption property compared to HNT@HKUST-1 composite. Gas adsorption capacity was analyzed by Brunauer-Emmett-Teller (BET) using N2 and CO2 gases. Specifically, EHNT@HKUST-1 composite showed enhanced CO2 gas adsorption capacity compared to HNT@HKSUT-1, being increased about 14.9 times, from 8.344 cm3(STP)g-1 to 19.332 cm3(STP)g-1. Additionally, HNT-NH2@HKUST-1 indicated around 24.849 cm3(STP)g-1 of CO2 gas adsorption capacity. These nanocomposites were analyzed by SEM, TEM-EDS and XRD in an effort to investigate the morphological and structural characteristics. This work can be a trigger to synthesize various hybrid nanotube materials for synergistic effects and applied to competitive adsorbents for gas capturing.

Resume : Acknowledgments This work has been supported by the Czech Science Foundation (ExPro project 19-27551X) References [1] W. J. Roth, O. V. Shvets, M. Shamzhy, P. Chlubná, M. Kubů, P. Nachtigal, J. Čejka, Journal of the American Chemical Society 2011, 133, 16, 6130–6133 [2] W. J. Roth, P. Nachtigall, R. E. Morris, P. S. Wheatley, V. R. Seymour, S. E. Ashbrook, P. Chlubná, L. Grajciar, M. Položij, A. Zukal, O. Shvets, J. Čejka, Nature Chemistry 2013, 5, 628–633 [3] S. E. Henkelis, M. Mazur, C. M. Rice, P. S. Wheatley, S. E. Ashbrook, R. E. Morris, Journal of the American Chemical Society 2019, 141, 4453−4459 [4] P. S. Wheatley, P. Eliášová, H. Greer, W. Zhou, V. R. Seymour, D. M. Dawson, S. E. Ashbrook, A. B. Pinar, L. B. McCusker, M. Opanasenko, J. Čejka, R. E. Morris Angewandte Chemie 2014, 53, 13210 –13214 [5] S. A. Morris, G. P. M. Bignami, Y. Tian, M. Navarro, D. S. Firth, J. Čejka, P. S. Wheatley, D. M. Dawson, W. A. Slawinski, D. S. Wragg, R. E. Morris, S. E. Ashbrook, Nature Chemistry 2017, 9, 1012–1018

Resume : Deposition allows to create thin films and layers on the functional materials that change the properties of bulk material. It opens a new opportunity for many applications in the research and industry. A variety of deposition methods were developed, including chemical and physical vapor deposition. They are based on material vapor which tends to impinge on the substrate. The thin layer is formed during exposition to volatile precursors in case of chemical deposition and in case of physical, the material vapor is gained from powder which is heated at high temperature and approaches to substrate. Nowadays it is possible to deposit thin film layers of different materials with accurate precision of nanometers, e.g. atomic layer deposition (ALD) and others. Whereas these methods are suitable for almost all inorganic and some organic materials, the problem occurs for the large organic molecules that need high temperature for evaporation from powder. At high temperatures the whole molecule can be eventually destroyed. Another problem is with bio-organics which cannot stand heating, like viruses, proteins, etc. There was some effort to deposit organics and bio-organics, but all methods had to face some problems. Typical example is electrospray deposition which uses liquid atomization by means of electrical forces generating a plume of droplets by charging the liquid at a high voltage [1]. Charged droplets are charging the insulating surface which can cause nuisance and the landing of the sprayed molecules is not soft which is destructive for them. There are few options to prevent these disadvantages by employing different methods, but they are really expensive, e. g. Electrospray Ion Beam Deposition method (ES-IBD) which consists of so called nano-electrospray, ion and electrostatic optics, quadrupole mass filter and time-of-flight [2]. However, these techniques can only be used with polar solvents, and typically deposition rates are very slow. One solution for deposition of these types of organics is a method called Atomic Layer Injection (further ALI) which is Pulsed Injection technique. Here, the injection of solution to the substrate in ultra-high vacuum chamber is performed. The injection is made by pulse valve which transforms solution to aerosol. The driving force for injection is given by argon gas which pushes the solution through pulse valve. The size of the drops of the aerosol can be controlled by adjusting the difference between pressure in the valve and pressure in the vacuum chamber. The solvent in droplets is evaporated during the flight, so only the molecules get on the substrate. The deposition by ALI method is suitable also for nanoparticles, nanotubes, pyrroles, polymers, bio-organics and other molecules. The main advantage consists of liquid phase of the solution with molecules which slows down the process of oxidation, e.g. ß-Carotene [3]. Other advantage is possibility to inject not just liquids but gases. The Atomic Layer Injection method allows to study properties of unconventional organic materials which have high potential in research and industrial field. It can achieve relatively high deposition rates. Furthermore, this technique is easy to use and cheap in compare to others. This technique in combination with annealing can provide deposing selfstructured layers. We present here initial results on deposition of single-molecule magnets (SMM) employing Atomic Layer Injection (ALI) technique. We tested [1,1’-Bis(diphenylphophino)ferrocene]dichlorcobalt(II) – DM18N and copper(II)dibenzoylmethane – Cu(dbm)2 molecules in powder. The molecular powder DM18N was dissolved in chloroform creating solution of concentration 3 mM. Second solution was prepared by mixing dimethylformamide solvent and Cu(dbm)2 molecular powder of concentration 1 mM. As substrates we chose Si(111) and Si(100) with Au layer coating because of its chemical stability. After deposition we observed real sample surfaces in Scanning electron microscopy to identify molecules in droplet formations. We also exploited Energy dispersive spectroscopy to confirm our presumptions. To assess their chemical composition, we used X-ray photoelectron spectroscopy (XPS). We proved that molecules are appearing preferentially on the edges of droplets area and stay in form of nanocrystals. The solvent creates coffee-ring stains. Later on, we found out that coffee ring stains can be suppressed by heating the sample. Acknowledgments This work was supported by the Central European Institute of Technology Brno (CEITEC) under Grants MEYS NSP II, Project No. LQ1601 (CEITEC 2020), MEYS InterExcellence (No. TC17021) and H2020 FET Open PETER (No. 767227). References [1] Elzoghby, A. O. Implications of Protein- and Peptide-Based Nanoparticles as Potential Vehicles for Anticancer Drugs. in Advances in Protein Chemistry and Structural Biology vol. 98 169–221 (Elsevier, 2015). [2] RAUSCHENBACH, S. Electrospray Ion Beam Deposition. Rauschenbach Research [online]. http://rauschenbach.chem.ox.ac.uk/home#methods [3] Courtesy of F. Himpsel and C. Rogero (NanoPhysics Lab, Centro de Física de Materiales CSIC-UPV/EHU, San Sebastián, Spain).

Resume : Zeolites are highly porous crystalline solids (mostly aluminosilicates) that comprise tetrahedrally-connected three dimensional frameworks and extra framework charge balancing cations. Their fascinating physical properties such as high sorption capacity, ion-exchange properties, shape selectivity and molecular sieving properties, catalytic activity allow to exploit them in various ways. Most widely these materials have found application as molecular sieves and heterogeneous catalysts in petrochemistry, oil refining and biomass conversion. Despite the fact, that aluminosilicates have been well studied and are commercially used, isomorphous replacement of Si+4 in the zeolite framework by cations other than Al3+ such as Fe3+ for tuning of catalytic properties of the material remains a field of extensive studies [1-3]. It is worth noting, that a few recent studies have assessed the effect of iron on the catalytic properties of Pd catalysts in the selective hydrogenation of unsaturated compounds. [4] Undoubtedly, most selective hydrogenation catalysts are based on supported Pd, Pt, and Rh, which are usually dispersed in form of small (nano) particles [5]. However, production and recovery of these noble metals is very energy consuming and expensive procedure. Thus, at least partial replacement of these metals by other inexpensive metals without sacrificing activity and selectivity of the catalysts would be a major technological breakthrough reducing the ecological footprint, catalyst cost and potentially increasing catalyst stability [5]. Iron is a promising component for this role as it is a non-toxic, inexpensive transition metal, which is abundant in nature and also potentially amenable to magnetic recovery [6,7,8]. Another important factor, which can affect the activity of these hydrogenation catalysts based on noble metal nanoparticles is the choice of a matrix or a support. Most common ways of such catalyst preparation include either encapsulation of the active metal nanoparticles in a porous matrix [9] or dispersing them on a high-surface support. Zeolites among other supports (carbon, metal oxides and others) have the advantage of shape selectivity which can optimize the outcome of reaction by increasing selectivity to the desired product. In this study we describe a proof of concept for preparation of bimetallic nanoparticles encapsulated into zeolite framework by reductive demetallation of Fe-zeolites. (Fig 1.) First step, involves direct synthesis of Fe-silicates with MFI framework topology using modification of method described by Ratnasamy [10] by increasing Fe-content in the synthesis mixture up to Si/Fe ratio 25-30. This procedure is followed by calcination of samples to remove the organic template. Then structural and textural properties, framework topology are analyzed using XRD, SEM, low temperature N2 adsorption, UV-Vis. In the next step, another metal is introduced into the synthesized zeolite via ion-exchange from the water solution. In this procedure the negative charge brought by the Fe3+ isomorphous incorporation in the zeolite framework is balanced by the second metal. At last, ion-exchanged sample is reduced in the flow of hydrogen at high temperature. This step combines reductive demetallation of Fe particles and alloying them with the second introduced metal. Finally, the outcome material represents a siliceous framework of MFI topology with bimetallic clusters encapsulated into zeolite channels.

Resume : Colloidal crystals made of sub-micrometer polymer particles are volumetric and low-effort materials that are highly attractive for visible light photonics, GHz phononics and superhydrophobic coatings, to name a few. Nevertheless, their fragility is one of the main aspects limiting their application. We demonstrated a new concept for uniform mechanical reinforcement of colloidal crystals by means of supercritical nitrogen and argon, at temperatures well below the glass transition. This method, termed cold soldering, is a synergistic combination of nanoscale plasticization of particles’ surface and compressive hydrostatic pressure. It results in the formation of permanent physical bonds between the particles while maintaining their shape and periodic arrangement. We employed Brillouin light scattering to monitor in-situ the mechanical vibrations of the crystal and thereby determine preferential pressure, temperature and time ranges for soldering This method offers a chemical-free and efficient solution for fabrication and tuning of durable devices and a potential remedy for the releasing of micro/nano contaminants into the environment. Moreover, the key idea of our approach, plasticization of polymeric nanostructures by means of gasses, remains an uncharted territory offering new effects and opportunities. Acknowledgements The work was supported by the Foundation for Polish Science (POIR.04.04.00-00-5D1B/18) and ERC AdG SmartPhon (Grant No. 694977).

Resume : High-entropy alloys (HEA), consisting of at least five elements with almost equiatomic concentrations, have received large attention from the scientific and technological community due to their remarkable properties such as high hardness, high strength, good fatigue and corrosion resistance, and high thermal stability. These superior characteristics are due to HEAs specific nanostructure, consisting of nanoscale particles embedded in an amorphous and/or crystalline matrix. The aim of this study was to evaluate the mechanical and tribological properties of (TiAl0.5CrNbY)Nx protective coatings at micro- and nano-scale. The metallic and nitride films of TiAl0.5CrNbY high entropy alloy were deposited at 300 0C on OLC45 and Si(100) substrates by a hybrid high power impulse magnetron sputtering (HiPIMS)/direct current magnetron sputtering (DCMS)/radio frequency magnetron sputtering (RFMS) technique. A con-focal unit, AJA ATC-ORION, was used, equipped with five unbalanced magnetrons fed by HiPIMS, DC and RF sources for simultaneous sputtering of elemental Al and Cr, Ti and Nb and Y targets, respectively, in inert Ar and reactive Ar N2 atmosphere. The hybrid deposition technique was used to improve the adhesion and to tailor the microstructure such as to obtain specific film properties. Films of (TiAl0.5CrNbY)Nx, where x= 0, 0.23, 0.42, with thicknesses in the range of 1-2 µm, were prepared and investigated for chemical composition, morphology, structure and microstructure, adhesion and micro- and nano-tribological and mechanical properties by EDX/XPS, AFM, nanoindentation, nanoscratch, nanowear, XRD and SEM. All films presented an amorphous structure. The nano-scale hardness increased from 7.7 GPa to 33.2 GPa with nitrogen addition, while the nano-scale friction coefficient decreased from about 0.3 to about 0.1. This work was carried out within the M.ERANET-6059-TriboHEA project funded by The Ministry of Education and Scientific Research, Romania, UEFISCDI Programme 3, grant no. 113/2019 and by The Ministry for Economic Development and Infrastructures, Basque Country, Spain, Hazitek Programme, grant no. ZL-2019/00622.

Resume : Samples of porous silicon nanowires were obtained by two step metal-assisted chemical etching (MACE) method using highly doped crystalline silicon wafers with a conductivity of <0.005 Ω*cm. The hydrogen peroxide (H2O2) concentration used in the MACE was changed from 5 to 30%. Scanning electron microscopy showed that the resulting samples have double porosity, and the concentration of H2O2 affects the structural properties of the obtained samples. The diameter of the porous silicon nanowires varied from 50 to 200 nm, and the thickness of the double porosity layer from 400 to 900 nm, depending on the concentration of H2O2. Porous silicon nanowires were located on top, and a layer of porous silicon was located on the bottom. The concentration of H2O2 also affected the ratio of nanowire thicknesses to the porous silicon layer. Using the theory of the Bruggemann effective medium approximation, the porosity of the samples was calculated from the IR reflection spectrum, which was 40-50%. Electron microscopy demonstrated the presence of a large number of silicon nanocrystals in the volume of nanowires. These nanocrystals showed visible photoluminescence due to quantum confinement effect and had a core-shell structure: a SiO2 shell and a crystalline silicon core. The results presented in this work can be used to create optical sensors and porous luminescent theranostic nanoagents based on porous silicon nanowires for applications in sensorics and biomedicine. The research was funded by the Russian Science Foundation (grant number 20-12-00297).

Resume : Transmission Electron Microscopy (TEM) represents a powerful technique for material characterization, nowadays reaching atomic resolution in both imaging and elemental analysis. Beyond the use of TEM as a mere characterization tool, the information got by TEM is paramount for fundamental research, to understand the mechanisms of nanostructures interaction and self-assembly. This issue is also key to address nanomaterials synthesis and to tailor their properties. For example, while the employment of pulsed spark discharges in liquids has emerged as an easy method to synthesize a wide spectrum of nanomaterials, it remains difficult to be controlled. In this work, we elucidate the growth mechanism leading to the selective synthesis of 2D mesoporous CuO agglomerates produced via pulsed spark discharges in water, thanks to the use of Atomic Resolution TEM. These nanostructures (sizes of 40-100 nm) are formed by the aggregation of small CuO nanocrystals (sizes between 3-5 nm). In our experiments, we exploited copper electrodes and water, and we selected four conditions by changing the voltage and pulse width. Atomic scale TEM analyses, in synergy with the electrical characterization of the discharge and the optical emission spectroscopy of the plasma radiation, led us to reconstruct the growth mechanism behind the 2D mesoporous CuO agglomerates self-assembly. We found that, although the material morphology and composition remain unchanged for all synthesis conditions, the crystal properties of the CuO nanoparticles can be finely tuned from mostly amorphous nanoparticles to high quality CuO nanocrystals. Moreover, while the CuO nanoparticles are almost spherical at lower pulse width, they become oblate at longer pulse width, reaching sizes of 6-8 nm in the elongated direction. Hence, at longer pulse width, the CuO nanoparticles are more densely packed in the 2D agglomerate. We describe the growth mechanism of the CuO agglomerates as follows. Since Cu and O species are detected in the plasma, CuO nanoparticles form during the discharge. Their crystal growth is sustained by the plasma, during a time interval that is related to the plasma dynamics, leading to the formation of elongated nanoparticles at longer pulse width. The increased density of the agglomerates and the crystallographic characteristics of the CuO nanoparticles at longer pulse width may be also regarded as a consequence of the further crystal growth at longer plasma lifetimes. To explain the agglomeration of the CuO nanoparticles, we invoked the pressure gradients existing within the plasma, which encourage the aggregation of the nanoparticles in 2D-structures. This study opens the route for pulsed spark discharges in water as a mean to produce 2D mesoporous CuO agglomerates and confirms atomic scale TEM as a powerful approach to get insight in nanomaterials growth. This project has received funding from the European Union’s Horizon 2020 programme under grant agreement No 823717 – ESTEEM3.

Resume : We present a pure blue fluorescent organic light emitting diode (OLED) where the emissive layer (EML) is composed of a host-guest matrix of 4,4’-di[N-carbazolyl] diphenyl (CBP, host) and 4,4’-Bis[(N-carbazole) styryl] biphenyl (BSB4, guest). The optimized concentration of the guest in the host matrix yields a Commission Internationale de l’Eclairage (CIE) coordinate of (0.15, 0.13) which is very close to the National Television Standards Committee (NTSC) standard of blue color (0.14, 0.08). The concentration of guest is optimized at 6 wt% with the help of photoluminescence (PL) studies. We study the effect of the organic layers in the OLED stack to balance the electron and hole concentration in the EML, thereby improving the efficiency and its roll-off. The charge carrier mobility and molecular energy levels of the organic materials are taken into consideration for this optimization. The optimized device yields a maximum external quantum efficiency (EQE) of 4.08%. This is very close to the theoretical limit for EQE (5%) of fluorescent OLEDs without the use of any light extraction layer.

Resume : In this work we design and study high efficiency orange-red Organic Light Emitting Diodes (OLEDs) with the thermally activated delayed fluorescence (TADF) near infra red material TPA-DCPP as the emission layer. We demonstrate increased efficiency by employing guest–host system with TPA-DCPP as guest and a material with bipolar characteristics as host. A detailed study of the photoluminescence (PL) is performed by growing films at different doping percentages on glass substrates. The doping concentration is optimized to achieve the high luminescence efficiency and the desired CIE coordinate (colour purity). We design the OLED stack layout and optimize the stack for achieving maximum electroluminescence efficiency by attaining the charge carrier balance in the emissive layer.. A detailed analysis of the effect of injection layers on the charge balance and device efficiency is presented. From the study, a high efficiency orange-red OLED with a maximum EQE of 13.2%, a CIE co ordinate of (0.64, 0.38) and maximum current efficiency of 8.65 Cd/A is demonstrated.

Resume : High-power ultrafast (femtosecond) laser processing has been attracting scientific attention as a perspective tool for thin amorphous hydrogenated silicon (a-Si:H) films modification [1]. Such treatment increases electric conductivity and optical absorption of the films due to formation of Si nanocrystals and surface roughness, which is promising for photovoltaics. During such processing, laser-induced periodic surface structures (LIPSS) might also be formed owing to interference of incident light with excited surface plasmon-polaritons [2]. The a-Si:H films modified by ultrashort laser pulses demonstrate electric anisotropy [2], birefringence and dichroism [3], which can be used in thin-film optoelectronics, sensors and anti-reflecting coating designing [1]. In the present work 600 nm thick undoped and 300 nm thick phosphorous-doped a-Si:H films were irradiated by femtosecond laser pulses (1250 nm, 125 fs, 10 Hz) in a raster mode. The films were irradiated at various scanning speed resulting into 30 or 700 laser pulses acting at each spot of the processed area. Formation of various LIPSS with periods from 0.88 to 1.12 μm and direction orthogonal or parallel to laser polarization was observed on the modified surfaces. Raman spectroscopy with excitation at 633 nm revealed nanocrystallization of irradiated films. Calculated from Raman spectra the crystalline silicon phase volume fraction value varied from 17 to 30% within the modified a-Si:H films. The sizes of silicon nanocrystals are varied from 3 to 6 nm for undoped a-Si and were significantly less for phosphorous-doped film (1.6 nm). This size difference may be associated with a larger number of defects in the doped film, which prevent nanocrystals growth. Due to laser-induced nanocrystallization the specific dark conductivity increases by 3 to 4 orders, up to 4•10^(–5) S/cm for the undoped films, and up to 11 S/cm for phosphorous-doped a-Si:H. The LIPSS formation also induced anisotropy of dark conductivity in the modified a-Si:H film surface plane. The ratios of the latter differ up to 4 times in mutually orthogonal directions for each sample. Observed effect may be explained both by a LIPSS depolarizing effect and an uneven crystalline phase distribution. The photoconductivity of the undoped films also demonstrated anisotropy. Based on photoconductivity spectral dependences and absorption coefficient spectra analysis, this effect can be explained by the charge carrier lifetime anisotropy caused by uneven distribution of crystalline phase within a-Si:H films. The work was supported by the joint grant of Moscow Government and Russian Foundation for Basic Research (project 19-32-70026). [1] A. Dostovalov, K. Bronnikov, V. Korolkov et al., Nanoscale, 12: 13431 (2020) [2] D.V. Shuleiko, F.V. Potemkin, I.A. Romanov, et al. Laser Phys. Lett. 15:056001 (2018) [3] R. Drevinskas, M. Beresna, M. Gecevičius, et al. Appl. Phys. Letters 106:171106 (2015)

Resume : Over the last few years, magnetic nanoparticles have gained increasing attention due to their potential use as building blocks for next-generation permanent magnets [1]. Among nanoparticles-based materials, ferrites with hexagonal structure such as SrFe₁₂O₁₉ (SFO) play an important role in the quest for new technological applications [2]. In particular, the inherent anisotropic shape of the crystallites in such hexagonal ferrites makes them interesting candidates for hard/soft exchange-coupled magnets, thus, leading to the need of a systematic study of the magnetic interactions in such systems. The aim of this work is to demonstrate the efficiency and reproducibility of the sol-gel approach in the synthesis of SFO nanocrystals. We have investigated the effect of different thermal treatments to vary the size of the nanocrystals, obtaining almost isotropic nanocrystallites, with a platelet-like shape. Through X-ray powder diffraction (XRPD), transmission electron microscopy (TEM), and magnetic measurements, it seems clear that a significant relation exists between the morphology (i.e., size and shape), and resultant magnetic properties of the hexagonal ferrite, which show a clear dependence on the platelet size along the c-axis. In particular, the evaluation of the magnetic performance for permanent magnet applications shows similar values in all the samples, thereby demonstrating the feasibility of optimizing the annealing temperature without any worsening of the physical properties. Furthermore, we show that the intrinsic magnetic properties of the hexaferrite can be significantly improved by substituting Fe³⁺ with other suitable ions, such as Al³⁺ , which produces a remarkable increase in the coercive field, up to ~1T. Finally, we also discuss the use of SFO in bi-magnetic nanocomposites, by coupling it with a well-known soft magnet, CoFe₂O₄, through a simultaneous biphasic synthesis route developed previously [3,4]. By tuning the effect of confinement during the growth of both phases, we were able to control the size and distribution of the hard/soft-phase regions, as well as to tune the magnetic anisotropy by chemical engineering. We thank the Swedish Energy Agency and Swedish Research Council (VR) for financially supporting this work. [1] B. Balamurugan, D. J. Sellmyer, G. C. Hadjipanayis, R. Skomski, Scripta Materialia 67, (2012) 542 [2] R. C. Pullar, Prog. Mater. Sci. 57, (2012) 1191 [3] G. Muscas, P. Anil Kumar, G. Barucca, G. Concas, G. Varvaro, R. Mathieu, D. Peddis, Nanoscale 8, (2016) 2081 [4] F. Sayed, G. Kotnana, G. Muscas, F. Locardi, A. Comite, G. Varvaro, D. Peddis, G. Barucca, R. Mathieu, and T. Sarkar, Nanoscale Advances, 2, (2020) 851

Resume : For functional materials, the multiscale modeling of material structures and morphologies is of increasing importance [1]. The consideration of stimulus-induced property changes and the calculation of atomistic material parameters plays a key role [1,2]. Based on this idea, a methodology for the multi-scale description of the behavior of piezoresistive polymers is presented. The piezoresistive properties of the material are characterized by the coupling of the mechanical and electronic behavior in the material, which also depends on the macroscopic device geometry. Specifically, we consider the application of such polymers as strain gauges on complex component surfaces [3,4]. Here, an isotropic strain determination in stress-increased surface areas shall be guaranteed. For this purpose we consider the bulk behavior as well as the interfacial behavior of the polymer. Exemplarily, we focus on Poly-3,4-ethylenedioxythiophene (PEDOT) based polymers. Our multiscale approach consists of three steps. In the first step, molecular dynamics based load simulations are facilitated [4]. For this we use a standard force field [5] to calculate all elements of the elastic tensor. To determine the electrical resistance, the distances between pairs of molecules are considered in an ab initio method [6,7,8] which allows it to eventually compute the electron mobility as a function of strain. Finally, finite element simulations are employed to describe the behavior at the interface between the polymer film and the surface of the component. Our methodology can be used to optimize existing piezoresistive polymers and predict the properties of new materials. References [1] Q. H. Zeng, A. B. Yu, G. Q. Lu, Prog. Polym. Sci. 2008, 33, 191 [2] Z. Wang, T. Wang, M. Zhuang, H. Xu, ACS Appl. Mater. Interfaces 2019, 11, 45301 [3] W. Fang, H. W. Jang, S. N. Leung, Composites Part B 2015, 83, 184 [4] K. Grabowski, P. Zbyrad, T. Uhl, W. J. Staszewski, P. Packo, Material Science 2017, 135, 169 [5] S. L. Mayo, B. D. Olafson, W. A. Goddard III, J. Phys. Chem. 1990, 94, 8897 [6] F. Günther, S. Gemming, G. Seifert, J. Phys. Chem. C 2016, 120, 9581 [7] S.-H. Wen, A. Li, J. Song, W.-Q. Deng, K.-L. Han, W.A. Goddard III, J. Phys. Chem. B 2009,113, 26, 8813 [8] A. Marutaphan, Y. Seekaew, C. Wongchoosuk, Nanoscale Research Letters 2017, 12, 90

Resume : Aqueous suspensions of porous silicon nanoparticles (PSiNPs) were prepared by mechanical milling of porous silicon nanowires, which were obtained by metal-assisted chemical etching (MACE). PSiNPs are porous particles with a diameter of about 90 nm. Such PSiNPs were previously reported to be effectively used in imaging, diagnostics, and treatments [1-3]. Unique features of PSiNPs are their biocompatibility and biodegradability resulted in formation of non-toxic silicic acid as a product [4,5]. In present work, the dynamics of PSi NPs dissolution was studied in model liquid, i.e. sodium phosphate buffer (PBS) and in living cells, using optical methods. Raman spectroscopy showed that incubation of PSiNPs in PBS at 37°C leads to their complete dissolution. This was indicated by the Si-related band shift to lower frequencies, the decrease of Raman intensity and eventual complete disappearance of the band after 24 hours of incubation. It has also been proven by vanishing of PSiNPs photoluminescence incubated for 24 hours in 3T3 NIH living cells. The results are promising for development of high payload biodegradable drug delivery systems. The reported study was funded by RFBR, project number 19-32-90122 and by the Russian Science Foundation, Grant No.19-72-10131. [1] Osminkina, L.A., Sivakov, V.A., Mysov, G.A. et al. Nanoparticles prepared from porous silicon nanowires for bio-imaging and sonodynamic therapy. Nanoscale Res Lett 9, 463 (2014). [2] Tolstik, E., Osminkina, L.A., Akimov, D.,et al. "Linear and non-linear optical imaging of cancer cells with silicon nanoparticles." International journal of molecular sciences 17.9 1536 (2016). [3] Gongalsky, M.,Gvindzhiliia, G., Tamarov, K.et al. Radiofrequency Hyperthermia of Cancer Cells Enhanced by Silicic Acid Ions Released During the Biodegradation of Porous Silicon Nanowires. ACS omega, 4(6), 10662(2019). [4] S. H. C. Anderson, H. Elliott, D. J. Wallis, et al.Physica Status Solidi (A) 197, 331 (2003). [5] Maximchik, P. V., Tamarov, K., ShevalE. et al.Biodegradable Porous Silicon Nanocontainers as an Effective Drug Carrier for Regulation of the Tumor Cell Death Pathways. ACS Biomaterials Science & Engineering, 5(11), 6063-6071 (2019).

Resume : Significant improvements in diagnostic analyses of biological tissues and radiation therapy of diseased tissues may be obtained injecting in them biocompatible metallic nanoparticles (NPs) at high adequate concentrations. In particular, Ag, Au and Bi NPs, generally with spherical shape and diameter lower than 20 nm, prepared by laser ablation in water as pure or as functionalized molecules, can be inserted in biological tissues and organs to enhance their equivalent atomic number. The small dimension and the functionality of the bio-molecules for living cells allow to introduce the NPs in the intracellular liquid through the cell membrane crossing, their diffusion toward the cell nucleus as well as their approach to the cellular DNA. This treatment, based on the increment of the local electron density, permits to improve the imaging diagnostics of the investigated tissues by using electron beams and X-rays, as well as the radiotherapy using X-rays, electron and ion beams. The high atomic number, in fact, enhances exponentially the X-ray absorption, the particle stopping power, the image contrast and the cellular DNA irreversible damage. The advantage to use biocompatible nanoparticles were demonstrated using different physical techniques, such as Raman, UV-VIS, FTIR, XRD and EDX spectroscopies. The high Z of the nanoparticles in the solution shows effects of surface plasmon resonance, high mass absorption coefficient for photoelectric X-ray interaction, high electronic and nuclear stopping powers for electron and ion beams, as well as cell inactivation and damage at high absorbed dose. Preliminary measurements in cell cultures and in living mice will be presented and discussed.

Resume : Free radicals (FR) are short-lived reactive chemical species with one or more unbound electron. They are expected to be linked to various pathogenic conditions which impact male fertility. On the other hand FR are also needed to maintain crucial physiological functions in sperms including capacitation. Several methods for free radicals detection have been applied to sperm cells, especially reactive oxygen species. Most of them are fluorescent dyes which usually bleach over time, and are not sensitive enough for small fluctuations in FR that trigger capacitation. Nanodiamond magnetometry potentially offers a complementary solution. It allows to measure nanoscale magnetic resonance signals with unprecedented sensitivity using the fluorescent nanodiamond (FND) probes. This is possible due to presence of nitrogen-vacancy centers (NVs) in a crystalline structure of FNDs. Since free radicals have a free electron spin, they cause a magnetic noise which can be measured and read out as an optical signal. In this study we have shown for the first time that fluorescent nanodiamonds can be used as probes for detection of free radicals in single sperm cells. We have used commercial 70 nm oxygen terminated FNDs as well as functionalized with human serum albumin or amino groups. Then highly motile boar sperms were selected and immobilized on dishes coated with fibronectin or hyaluronic acid. Cells were incubated in Human Tubal Fluid (HTF) in order to induce their capacitation or modified-HTF (HTF medium without bicarbonate, calcium salts and serum) to keep them in an uncapacitated state. Both variants were treated with various concentrations of FNDs. The biocompatibility of probe was evaluated using MTT, DCFDA and membrane integrity assay. It has been found that at low concentration (1 µg/ml) nanodiamonds do not have any adverse effect on spermatozoa. Confocal and scanning microscopy images have shown that FNDs preferentially attached to the head of sperm cells. Finally, based on the T1 relaxation measurements inspired by equivalent concept in MRI, preformed on our home-built microscope we were able to evaluate changes in the amount of free radicals, in a single spermatozoa, before and after capacitation. These proof-of-concept experiments show that nanodiamonds magnetometry is promising tool for future clinical studies of correlation between free radicals production and male infertility

Resume : The organic semiconductors have emerged as a promising candidate in the optoelectronic industry due to their economical fabrication method over a large area. Due to the amorphous nature and structural disorder of these materials, there are defects in the systems which affect the optical and electrical properties. Although the spectroscopic techniques such as capacitance-voltage measurement, impedance spectroscopy, deep level transient spectroscopy (DLTS) can be used to determine the density of defect states and their energies, probing the deep traps and mid-gap traps in these systems are difficult. Apart from the DLTS, the other techniques focus only on the study of the shallow traps in the system. Here, we use electroabsorption (EA) spectroscopy to study the deep trap states in the P3HT, a well-studied organic photovoltaic system. The variation of EA signal with the applied DC bias shows a non-linear behavior as the voltage is changed to forward bias from the reverse bias. This deviation from the ideal case increases with the applied forward bias. This suggests a non-uniform distribution of the electric field inside the device. We attribute this non-uniformity to the accumulated charges near the electrodes and the trapped carriers in bulk and the interface of the device. We investigate the energy of the trapped carriers from the temporal evolution of the EA signal. The large decay time suggests the presence of deep trap states (at 752 meV and 813 meV) in the P3HT. The density of the trap states is also estimated from the strength of the EA signal in the forward bias.

Resume : The explosive wireless technology by utilizing electronic systems in civil and military applications unavoidably generate the pollution known as the electromagnetic interference, so lightweight materials with high absorbing efficiency in over broaden bandwidth are highly in demands. In this work, a hybrid composite absorber constructed from reduced graphene oxide (rGO) and amine-functionalized NiO/ZnO was prepared via in situ reaction, which consisted a pyrolysis and surface modification of a heterobimetallic Ni-Zn-based metal-organic framework. The rGO sheet were found to graft successfully on the surface of NiO/ZnO. The hybrid displayed an excellent microwave absorbing performance in polystyrene matrix. The optimal minimum reflection loss reached to -42.5 dB at 13.7 GHz at the coating thickness of only 2.15 mm with 4.5 GHz effective absorption frequency bandwidth, corresponding to a reflection loss less than -10 dB (90% absorption). The grafting of rGO not only resulted the hybrid composite in larger contact area, but also benefited synergistic effects with NiO/ZnO to endow electromagnetic waves absorbing performance. The absorbing mechanism was mainly contributed to the enrichment of interfacial polarization, dipole polarization, dielectric loss followed by multiple reflection and scattering.

Resume : The level of meat freshness can be evaluated by monitoring the quantity of histamine. By measuring the level of histamine in a food product, we can easily detect early onset of spoilage, thus reducing foodborne poisoning (by identifying contaminated products) and food waste (by recycling products that are edible). In this respect, carbon-based screen printed electrodes (C-SPE) have been functionalized with two different metallo-porphyrins (Mn and Zn) and their response to different concentrations of histamine was recorded via cyclic voltammetry. Real-world samples (commercially available meat samples) were also used for the extraction of histamine and tested in the same conditions as the standard concentration samples. The C-SPE modified with metallo-porphyrins showed increased selectivity towards histamine as well as a decrease in the oxidation potential due to an improved electron transfer between the molecular complex trichloroacetic acid-histamine and the metallo-porphyrins [1,2]. This interaction was modelled using HyperChem® software and the activation energy for each metallo-porphyrin was estimated. The limit of detection for histamine has been calculated as 0.7 ppm. Keywords: histamine detection, porphyrin functionalization, screen printed electrode, electrochemistry, meat freshness. Acknowledgements: This work was supported by a grant of the Romanian Ministry of Education and Research, CNCS - UEFISCDI, project number PN-III-P1-1.1-PD-2019-1134, within PNCDI III, CORE Programme, Ctr. 18/N/2019 and Contract nr.19PFE/17.10.2018 financed by Ministry of Research and Innovation. References: [1] A.-M. Iordache, R. Cristescu, E. Fagadar-Cosma, A. C. Popescu, A. A. Ciucu, S. M. IORDACHE, A. Balan, C. Nichita, I. Stamatin, D. B. Chrisey, Histamine detection using functionalized porphyrin as electrochemical mediator, Comptes Rendus Chimie, 21 (3-4), 270-276 (2018), WOS:000428095300013; DOI: 10.1016/j.crci.2017.05.008 [2] S. IORDACHE, R. Cristescu, A. C. Popescu, C. E. Popescu, G. Dorcioman, I. N. Mihailescu, A. A. Ciucu, A. Balan, I. Stamatin, E. Fagadar-Cosma, and D.B. Chrisey, Functionalized porphyrin conjugate thin films deposited by matrix assisted pulsed laser evaporation, Applied Surface Science 278 (2013) 207–210; WOS:000320598300041.

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