Seznam abstraktů 2024: POSTEROVÁ SEKCE A

Plasma polymerization, commonly considered a type of plasma-enhanced chemical vapour deposition (PECVD), is a popular method for depositing organic thin films. However, it often produces films with limited molecular complexity due to the necessity to use relatively low molar mass precursors that can be vaporized. To address these limitations, plasma-assisted vapour thermal deposition (PAVTD) was developed. In PAVTD, a solid polymer undergoes thermal degradation (evaporation) in a crucible, producing oligomers with higher molar masses (10^2-10^3 g/mol) than typical PECVD precursors. These oligomers are then re-polymerized in RF plasma, allowing PAVTD films to exhibit properties characteristic of classical polymer physics and chemistry, a rarity for plasma polymers. This process enables the precise control of properties such as biodegradability and hydrolyzability, as demonstrated in polylactic acid (PLA)-based films.
PAVTD effectively bridges the gap between classical and plasma polymers. To enhance stability and deposition rates, continuous-PAVTD has been developed using standard FDM 3D printing filaments, achieving deposition rates up to several nanometers per second. This advancement addresses deposition duration and stability issues, making PAVTD a practical tool for studying plasma polymerization. Furthermore, PAVTD can be combined with other vacuum-based thin film deposition techniques like gas aggregation source of nanoparticles (GAS). This capability was demonstrated by fabricating Cu:PLA-like nanocomposite-based distributed Bragg reflectors (DBR), where the reproducibility of the deposition rate matters significantly. This reflector was tested as a gas sensor for ethanol vapours, exhibiting strong reflectance peak shifts.

Traditional strategies for enhancing photocatalytic activity focus on tuning visible light response, crystal facets, and nanocrystal shape. Here, we used defect engineering approach to design efficient photocatalysts with substrate-specific reactivity. Platinized, defective anisotropic brookite TiO2 photocatalysts exhibit up to an 11-fold increase in methanol oxidation rate compared to pristine brookite, with much lower rates for ethanol and isopropanol. We demonstrate that increased alcohol oxidation boosts hydrogen evolution, with reduced anisotropic brookite showing up to 18-fold higher photoactivity than anatase and isotropic brookite nanocrystals. Controlled engineering of oxygen vacancies and lattice strain generates large electron polarons that host substrate-specific active sites for alcohol photo-oxidation. Photoluminescence excitation spectroscopy of charge carrier recombination in stoichiometric and reduced brookite nanorods identifies specific photoluminescence enhancement in reduced brookite, indicating conduction band electron injection during ethanol photo-oxidation. This explains their exceptional reactivity and efficient hydrogen generation.

The main objective of this study was to investigate the feasibility of preparing an electrically conductive composite containing graphite or graphene from a glucose-montmorillonite (MMT) nanocomposite. Four different ratios of crystalline glucose and MMT were mixed, thoroughly combined in a mortar, pressed into tablets, and calcined at 1300 °C. To understand the impact of calcination, the electrical conductivity of both non-calcined powder samples and pressed tablets was measured. The tablets were damaged during high-temperature calcination, so the calcined samples were crushed in a mortar for further testing. Various analytical techniques were used to characterize both calcined and non-calcined samples. X-ray diffraction (XRD) determined the crystalline structure and identified any new phases formed during calcination. Raman microscopy studied the presence of graphite or graphene. Transmission electron microscopy (TEM) provided an in-depth observation of the microstructure, revealing whether the layers in the samples matched the distances associated with graphite or graphene. Thermogravimetric analysis (TGA) assessed the thermal stability and composition of the samples. Elemental analysis examined the effect of glucose content before calcination and the carbonaceous content in the calcined samples. The combined results confirmed that calcination has an impact on electrical conductivity thanks to the formation of conductive carbon material, with the final properties dependent on the ratio of MMT to glucose. This work was supported by the SGS project no. SP2024/041.

rGO-CeO2 nanocomposite has been applied in the field of electrochemical sensors, which leads to a significant improvement for this type of sensors in terms of facility, sensitivity, and accuracy. Additionally, it is well known that synthesis procedures play an important role in the structure of nanomaterials (e.g., morphology), which in turn has a big impact on various properties. Hence, it is necessary to investigate the effect of synthesis procedures on characteristics of this nanocomposite to maximize the electrochemical performance (e.g., enhancing limit of detection) of the sensor using rGO-CeO2. In this study, two different approaches, namely in situ and ex situ methods, were used to synthesize GO-CeO2, then GO-CeO2 was reduced by hydrazine to form the final product rGO-CeO2. Subsequently, the morphology and elemental analysis/mapping of this nanocomposite were examined by Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy, respectively. Afterwards, the nanocomposites were drop-casted on the surface of glassy carbon electrode, and the electrochemical properties, namely electroactive surface area and charge transfer resistance, were evaluated by Cyclic Voltammetry and Electrochemical Impedance Spectroscopy in the presence of ferrocyanide/ferricyanide redox probe. The results indicated that CeO2 nanoparticles were evenly distributed on the surface of wrinkled rGO sheets, and the nanocomposites from both approaches improved the electrochemical properties in comparison to bare glassy carbon electrode.

A carbonaceous coating on a carbonaceous matrix was synthesized by the modified chemical vapor deposition (CVD) method. The specific morphology of the coating, with graphitic spikes protruding from the substrate and connected by fringes of multilayer graphene materials, was observed by scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). X-ray diffraction (XRD) and Raman microspectroscopy demonstrated the coating's crystalline nature, with increased crystallinity leading to improved thermal resistance of the coated carbonaceous matrix in the presence of an oxygen atmosphere. The unique surface of the carbonaceous materials and their increased heat resistance make them intriguing for composite material applications.

Simulating and characterizing physical systems is one of the most promising applications of quantum computing. In our research, we focused on electronic structure calculations of GaAs using quantum computer simulator. This work explores the binary crystal gallium arsenide, employing Variational Quantum Deflation (VQD) and the Subspace-Search Variational Quantum Eigensolver (SSVQE) to access the full energy spectrum. A tight-binding Hamiltonian is used to investigate the effects of optimization methods, hyperparameter tuning, and quantum circuit architecture on the performance of these variational quantum algorithms. Our findings show that higher-energy states require more iterations for accurate evaluation, with the Constrained Optimization BY Linear Approximation (COBYLA) method proving to be the most effective.

Lead-salt (IV-VI) semiconductor quantum dots (QDs) have been extensively investigated as highly promising fluorescent materials due to their many attractive features, including a simple, highly symmetric crystal structure, small bulk bandgaps, large exciton Bohr radii, and narrow emission spectra. Small PbS QDs (~a few nm) emitting in the near-infrared (NIR) range are of significant current interest, particularly in the fields of infrared photodetectors, solar cells, and biomedical imaging. However, little progress has been made in exploring mechanisms to manipulate their optical properties, such as lifetimes and lifetime distributions, which substantially limits the broader application of PbS QDs.
We found that the excited-state dynamics of PbS QDs can be significantly altered by concentration-driven ligand dynamics, as well as by experimental parameters such as excitation pulse duration and laser power. We describe these effects in detail using a combination of spectroscopic techniques, including absorption, photoluminescence (PL), time-resolved PL kinetics, and transient absorption measurements. We demonstrate a distinct peak in lifetime spectral dispersion and show that it can be adjusted by varying the volume of added ligand molecules. By modulating the excitation pulse duration, we demonstrate the ability to manipulate the lifetime distributions.
We believe that our findings suggest a new design principle for bright NIR-emitting PbS QDs with enhanced PL, which are urgently needed for a wide range of applications requiring microsecond-range lifetimes. Furthermore, our study emphasizes the critical role of capping ligands and experimental conditions in determining the PL properties of PbS QDs.

Optical metasurfaces, ultrathin, nanoscale structures capable of precisely controlling light, offer compact alternatives to traditional bulky optical components. However, a major challenge remains in achieving their effective electrical tunability, which is crucial for creating active, reconfigurable devices. Traditional approaches using plasmonic or Mie resonances have been limited in this respect. Our research explores the potential of harvesting the excitonic resonances in all-inorganic metal halide perovskite CsPbBr3, since it supports room-temperature stable excitonic states and exhibits highly tunable optical properties across the visible spectrum. These attributes are making CsPbBr3 an ideal candidate for electrically tunable optical metasurfaces. We aim to demonstrate a novel on-chip nanolasing device utilizing a CsPbBr3 micro-resonator. Furthermore, by investigating the voltage-dependent behavior of exciton resonances, we seek to create a nanolaser with distinct ON/OFF states, advancing the functionality of active metasurfaces. This research has significant implications for the future of quantum communication technologies, where precise control of excitonic properties is essential.

Ni-Mn-Ga alloy is the most promising candidate as material for magnetic shape memory applications. In addition to austenite, it is also found in variety of martensite phases. Antiphase boundaries (APBs) are planar defects that play a critical role in strengthening Ni-based alloys, and their sensitivity to alloy composition offers a flexible tuning parameter for alloy design.
We combine experimental and theoretical (ab initio) methods to analyze the stability and magnetic order in the vicinity of an antiphase boundary in Ni2MnGa possessing L21 order. Ab initio electronic structure calculations based on density functional theory are used to investigate the magnetic order in structure simulating APBs in cubic austenite. Total energy calculations indicate that at the interface, the ferromagnetic arrangement changes its orientation in the opposite direction. This sudden change in magnetization is observed in microscope images by magnetic force microscopy. The images are shown and discussed.

The combination of plasma enhanced chemical vapor deposition and vacuum evaporation at one vacuum chamber is in situ method how to integrate metallic (Sn) and semiconductors (Ge) nanoparticles into amorphous hydrogenated thin films and their structures on the base of a-Si:H or a-SiC:H. The transmission and scanning electron microscopy and atomic force microscopy structures are used for their microscopical characterization while the photothermal deflection spectroscopy and photoluminescence spectroscopy are used for spectroscopical characterization. For the final characterization of the electronic properties is used the measurement of temperature dependence of electrical conductivity with evaluation of the activation energy.
ACKNOWLEDGEMENTS: The work was supported by the Czech Science Foundation project 24-10607J. This work has used the large research infrastructure CzechNanolab supported by the MEYS through the project No. LM2023051.

In order to overcome the restacking problem of 2D materials, different approaches to designing MXene into 3D structures have been studied extensively. One material that has attracted considerable attention in this context is fluorine-terminated yttrium carbide (Y2CF2). Herein, we have investigated the structural and electronic properties of Y2CF2 as a pure 3D crystalline stack of MXene-like sheets by using different density functional theory (DFT) exchange-correlation functionals. We first focused on interlayer interactions, possible stacking conformers, and stability. Next, we aimed to explore the optical, mechanical, and thermal properties of both the 3D crystalline structure and its 2D constituent.

Hydrogen and oxygen evolution reactions (HER and OER) are crucial for the development of water splitting processes and green hydrogen production that meet the energy demands of modern society. The efficiency of these electrode reactions is primarily governed by the nanostructure and chemical reactivity of the components present in the electrocatalyst.
This work aims to generate hybrid materials based on graphene oxide (GO) and an organometallic η6-areneruthenium coordination polymer containing 1,3,5-benzenetriacetate as a bridging ligand, for constructing electrodes for HER and OER. Two types of deposition methods were tested: dip-coating and the Langmuir-Blodgett (LB) method.
After obtaining the GO films, they were alternately immersed in η6-areneruthenium and benzenetriacetate solutions for varying durations (from 5 to 30 minutes). The films were characterized by spectroscopic techniques. Linear sweep and cyclic voltammetry were performed in a 3 mol·L-1 NaCl solution.
The best performance was achieved by the films deposited using the LB method, which generated cathodic currents per mass per area of nanocatalyst in HER that were eight thousand times higher than the analogous dip-coated films at the same mild potential. These results revealed the influence of the heterostructure in the electrocatalytic activity, that present higher efficiencies and more rational use of resources.

Photoactivation of aspartic acid-based carbon dots (Asp-CDs) induces the generation of spin-separated species, including electron/hole (e−/h+) polarons and spin-coupled triplet states, as uniquely confirmed by the light-induced electron paramagnetic resonance spectroscopy. The relative population of the e−/h+ pairs and triplet species depends on the solvent polarity, featuring a substantial stabilization of the triplet state in a non-polar environment (benzene). The electronic properties of the photoexcited Asp-CDs emerge from their spatial organization being interpreted as multi-layer assemblies containing a hydrophobic carbonaceous core and a hydrophilic oxygen and nitrogen functionalized surface. The system properties are dissected theoretically by density functional theory in combination with molecular dynamics simulations on quasi-spherical assemblies of size-variant flakelike model systems, revealing the importance of size dependence and interlayer effects. The formation of the spin-separated states in Asp-CDs enables the photoproduction of hydrogen peroxide (H2O2) from water and water/2-propanol mixture via a water oxidation reaction.

Environmental cleanliness is of paramount importance in maintaining a high quality of life on Earth. This study integrates the mass quartz crystal microbalance (QCM) and conductive interdigital transducer (IDT) metallization in a hybrid sensor. The active layer of the sensor compromises hydrogen-terminated nanocrystalline diamond (H-NCD), which is a highly intriguing wide-bandgap material known as well responsive to a range of external stimuli, including oxidizing and reducing gases, light illumination, bio molecules, and other surrounding conditions. The H-NCD exhibits distinctive properties in induced subsurface p-type conductivity, also known as two-dimensional hole gas (2DHG), which is sensitive to exposed gases or organic molecules. To fabricate the hybrid sensor, the QCM crystal was initially coated with a thin H NCD layer. The IDT structure was then printed on this structure using the ink-jet method with silver ink. The high thermal conductivity of the diamond layer enhanced the print quality, as the ink dried more rapidly and increased the resolution of the printed structures. The IDT structures were dried by annealing process at 150°C for one hour. This hybrid sensor employs two distinct detection principles: the QCM component responds to the mass of bound molecules on the sensor’s surface while the IDT measures the conductivity changes within the subsurface 2DHG layer due to the charge transport/exchange between diamond and gas molecules. These complementary sensing principles form a hybrid sensor with enhanced detection capability and selectivity for environmental influences compared to individual sensors.

Optically active diamond structures have gained significant importance as the material of choice for biological, optoelectronic, and quantum sensing applications. In this sense, ultrananocrystalline diamond (UNCD) films incorporating photoluminescent color centres have emerged as promising initial material for fabrication of diamond nanoparticles and membranes. Especially, negatively-charged silicon-vacancy color centers (SiV) in diamond are often inflected due to the bright and spectrally narrow photoluminescence (PL) at room temperature, with a short decay time and high photostability.
This study focuses on the synthesis and optical properties of UNCD films with SiV centers fabricated by chemical vapor deposition (CVD) method, where SiV are incorporated into diamond either from solid silicon source or silane as gas silicon source. The incorporation and characteristics of SiV centers from both sources were critically evaluated. Additionally, we present a molten salt thermal etching (MSTE) process as a perspective approach for future nanoparticles and membranes creation from UNCD films.
Our results demonstrate a versatile approach to UNCD growth and modification that offers controllable porosity and concentration of SiV centers. This method opens the way to advanced quantum sensing applications. The findings of this study contribute to the growing body of knowledge on diamond-based materials for quantum technologies and nanoscale sensing.
This work was supported by the MEYS project Mobility plus DAAD 24-13 and the bilateral GACR LA project no. 23-04322L.

This study presents a novel approach for fabricating self-standing diamond films with tailorable cavities, eliminating the need for reactive ion etching (RIE). We employed selective area deposition on SiO2/Si substrates in a microwave plasma CVD system at high temperatures (1000°C). The method exploits the thermal expansion mismatch between diamond and SiO₂/Si substrates to induce film delamination, resulting in free-standing structures. Diamond films with thicknesses of approximately 50 μm were produced, featuring cavities whose dimensions could be controlled by lithography mask dimensions and deposition time. Raman spectroscopy confirmed the high quality of the diamond films, showing a dominant peak centered at 1330 cm⁻¹. The presented technological approach offers a promising solution for microstructuring of diamond films with potential applications in high-tech applications.

In this work, the nominally undoped and In, Ga and Al-doped ZnO thin films were pulsed laser deposited (PLD) on sapphire substrates and tested for potential applications in photodetector devices. Optical measurements by photothermal deflection spectroscopy (PDS) show a systematic change in the optical absorption edge and Urbach energy with increasing doping concentration, indicating a modification of the electronic structure and defect states. Complementary photoluminescence (PL) spectra were acquired to elucidate the radiative recombination processes and defect-related emissions in the ZnO films. The PL data corroborated the PDS findings, showing a shift in the near-band-edge emission and changes in defect-related peaks as a function of In (Ga, Al) doping. Impedance spectroscopy was employed to investigate the electrical properties and charge transport mechanisms in the ZnO films. The IS data were analyzed using equivalent circuit models to extract key parameters such as carrier concentration, mobility, and interfacial resistance.
The combined analysis provided a comprehensive understanding of the optoelectronic properties of ZnO films. The findings suggest that optimized doping can enhance the photoresponse and charge transport properties of ZnO, making ZnO a promising material for high-performance photodetector applications.
The work was supported by the Czech Science Foundation project 24-10607J, Ministry of Education, Youth and Sports of Czech Republic (MEYS) Danube project 8X23025 and the Mobility Plus project SAV-23-13 (CAS-SAS-2022-08). The authors also acknowledge the Czech Ministry of Education, Youth and Sports grant no. CZ.02.01.01/00/22_008/0004617 − "Energy conversion and storage".

This study investigates the real-time formation of Pseudomonas syringae pathovar morsprunorum CCM 2534 (Psm) biofilms, a novel dual-sensing approach integrating attenuated total reflection Fourier-transform infrared (ATR FT-IR) spectroscopy and impedance spectroscopy under continuous medium flow.
While ATR FT-IR effectively characterizes the initial stages of biofilm formation, particularly adhesion and early development, it may provide limited information on the growth and maturation of biofilms with tall structures (mushroom-shaped microcolonies). To address this limitation, we employed complementary impedance measurements.
ATR FT-IR spectra of the Psm biofilm, recorded within the 4000-800 cm-1 spectral window, revealed characteristic absorption bands at 1141-1006 cm-1, 1420-1380 cm-1, 1580-1490 cm-1, and 2935-2915 cm-1. The integrated areas of these bands were utilized to monitor the progression of individual phases of Psm biofilm development, including inoculation, washing, recolonization, restructuring, and maturation.
Impedance measurements, conducted with a constant voltage of 500 mV over a frequency range of 10 Hz to 100 kHz, enabled a comprehensive analysis of biofilm growth due to varying current paths through/around the Psm cells. This technique showed promise in capturing the later stages of Psm biofilm development, particularly data recorded at lower frequencies during the first 72 hours. However, further optimization of impedance measurements is necessary to establish this approach as a reliable complement to ATR FT-IR for long-term monitoring.
This dual-sensing technique offers a promising perspective for in-depth, real-time analysis of biofilm formation, potentially advancing our understanding of microbial colonization processes.

Fe-Ni-based nanoparticles are promising materials for the production of high-performance permanent magnets. The research explores the preparation of Fe-Ni alloys using iron-nickel oxalate precursors, which were synthesized via the coprecipitation method and subsequently reduced in a hydrogen atmosphere. One of the aims of the work is to compare the effect of different methods of preparation of precursors on the particle size and composition of the resulting materials. Structural, magnetic, and morphological properties were analysed using a combination of Mössbauer spectroscopy, X-ray powder diffraction (XRD), and scanning electron microscopy (SEM).
The relative proportions of iron and nickel content in the prepared oxalate precursors were approximately 50% by weight, according to EDS analysis. The precursor samples consisted of clusters of particles with undefined shapes, exhibiting a wide range of particle sizes. After annealing, multiple Fe-Ni phases were present in the sample. Structure investigation and magnetic measurements confirmed the formation of phases suitable for magnetic applications.

The construction industry faces increasing demand for alternative raw materials due to resource depletion. Recycled glass waste has been proposed as a partial replacement for sand in concrete. However, the macroscopic properties of concrete and cementitious composites are influenced by the initial properties of their components and their interactions, necessitating precise bulk & surface analysis and modification(s).
This study enhances previous observation on plasma-treated ground glass waste (GGW) which surface modifications were detected via changes in photoluminescence [10.3390/nano14131091]. We continue this research by using another surface-sensitive method, Kelvin probe, which measures the contact potential difference (CPD) between the studied material and a probe that can be next recalculated to work function (WF). However, accurate measurement requires the probe to be calibrated on a material of known WF, which is still a challenging task due to the high fluctuations in WF values (e.g. gold WF is reported in the range 5.0-5.4 eV).
We use a more reliable Kelvin probe calibration procedure using a set of 6 metals with different WFs to address the variability in the WF values above-mentioned. The probe WF is obtained from the intercept of the linear fit of the data which resulted in WF of 5.15 eV in our case. Such a calibration method provides consistent and reproducible values over months.
As a result, we observed only negligible WF shifts for the differently treated GGW, most likely because of its insulating nature and/or still too small surface to volume ratio. Furthermore, this methodology was validated by investigation of another nanoscopic material of not yet proved electrical conductivity - nanodiamonds. We investigated the size-dependence of nanodiamonds (diamond nanoparticles in the range of 18 - 125 nm) WF as a function of hydrogenation temperature (800 - 1000°C). We obtained consistent results and found a local minimum of WF at 4.5 eV for 50 nm nanodiamonds hydrogenated at 900 and 1000°C. The results will be discussed considering the influence of surface areas, film thicknesses, and electrical, physical, and chemical properties of the materials. These findings contribute to the understanding of surface properties in recycled materials on nano-sized dimensions, potentially finding future applications in the construction industry.

Quantum computing is a newly emerging information-processing technology that is foreseen to be exponentially faster than classical supercomputers. Current quantum processors are nevertheless very limited in their availability and performance and many important software tools for them do not exist yet. Therefore, various systems are studied by simulating the run of quantum computers. Building upon our previous experience with quantum computing of small molecular systems (see I. Miháliková et al., Molecules 27 (2022) 597, and I. Miháliková et al., Nanomaterials 2022, 12, 243), we have recently focused on computing electronic structure of periodic crystalline materials. Being inspired by the work of Cerasoli et al. (Phys. Chem. Chem. Phys., 2020, 22, 21816), we have used a hybrid variational quantum deflation (VQD) algorithm, which combined classical and quantum information processing. Employing a tight-binding type of crystal description, we present our results for crystalline diamond-structure materials, such as Sn or Si. In particular, we focus on the states along the lowest occupied band within the electronic structure of Sn and compare the results with values obtained by classical means. While we demonstrate an excellent agreement between classical and quantum-computed results in most of our calculations, we further critically check the sensitivity of our results with respect to computational set-up in our quantum-computing study.

This study is focused on the covalent grafting of the carbonyl iron (CI) particles with poly(2-(trimethylsilyloxy)ethyl methacrylate) (PHEMATMS) using ATRP approach. In the first step the CI particles were grated with PHEMATMS brushes and in the second step each brush structure was further grafted with another PHEMATMS chain to create the dendritic-like shape. In this respect, the first generation (brushes) and second generation (dendrites) were confirmed using GPC and NMR investigations. The presence of the in nano-sized layer grafted PHEMATMS on the CI particles was elucidated using TEM and SEM-EDS investigations. The enhanced compatibility with silicon oil and silicon elastomer was investigated using contact angle measurements. The stability of CI-brush and CI-dendritic particles in silicone oil suspension and also their enhanced compatibility in silicone elastomer was thoroughly investigated using sedimentation stability approach and rheological investigation, respectively. Finally, it will be presented the crucial impact of the grafting on the overall magneto-responsive capabilities.
ACKNOWLEDGEMENT: Authors acknowledge to the Czech Science Foundation no. 23-07244S for financial support.

MAX phase materials are nano-layered, hexagonal, machinable, early transition-metal carbides, and nitrides, where M is a transition metal, A is an element of the A-group (mostly groups 13 and 14), and X is C and/or N. These phases exhibit a unique combination of both metallic and ceramic properties.
In this study, the Ti-Al-C MAX phases were prepared. In the case of the Ti-based MAX phases, Ti, Al, and C powders are used for synthesis. Physical and technological troubles usually affect the synthesis of MAX phases, resulting in decreased yields of the MAX phase and promoting the formation of undesirable phases. For example, the titanium carbide TiC and the Al3Ti, TiAl and Ti3Al intermetallics can also be formed under the synthesis process of the Ti3AlC2 MAX phase. Additionally, Al is oxidized, and Al2O3 occurs often. The successful preparation of MAX phases depends on various conditions such as: heating temperature, holding time, purity of inert atmosphere, heating rate, or gas flow. In our study, we used the thermal analysis method to find optimal conditions to obtain a Ti3AlC2 phase. MAX phase evolution during different conditions was analyzed using powder X-ray diffraction.
ACKNOWLEDGEMENTS: This research was supported by project No. CZ.02.01.01/00/22_008/0004631 Materials and technologies for sustainable development within the Jan Amos Komensky Operational Program financed by the European Union and from the state budget of the Czech Republic. Authors also thank the VSB-Technical University of Ostrava project SP2024/025) for the financial support.

In this work, a Hysitron TI 950 instrument equipped with an xSol 800 stage (Bruker) has been used to evaluate the mechanical properties of selected materials. The hardness and reduced elastic modulus of the coatings have been measured both at room temperature and elevated temperatures. The measurement of the thermal dependence of the mechanical properties was carried out in steps with an increase of 50 degrees C starting from 24 degrees C up to 600 degrees C. At each temperature step system calibration procedures after each 10 indentations were performed.
ACKNOWLEDGEMENTS: This research has been supported by the Czech Science Foundation under project GA23-06263S. We acknowledge CzechNanoLab Research Infrastructure supported by MEYS CR (LM2018110).

Actually, Boron Nitride nanotubes (BNNT) have received great interest as material dedicated to many applications such as electronic and thermoelectrical devices.
This work is a theoretical study of the structural, electronic and thermic transport properties of pure and iron (Fe) doped Boron Nitride nanotubes (BNNT) in its hexagonal phase (h-BN).
This theoretical study was performed with the CRYSTAL program (www.crystal.unito.it) providing crystalline orbitals built on localized orbitals at the DFT (B3LYP hybrid hamiltonian) level of approximation.
We have shown that Fe-doping nanotubes could behave as narrow bandgap semiconductors, the presence of Fe atoms modifying the gap value because of the presence of sates participating to the thermoelectrical transport.
Our calculations show that the undoped nanotubes are ceramic materials with a large band gap around 6 eV while this latter value can be divided by 2 when the nanotube is doped by Fe. The related Seebeck coefficient, and electrical and thermal conductivity properties allow to deduce the values of the figure of merit ZT. Obtained results indicate that BNNT can be considered promising as thermoelectrical materials.

Owing to its unique physical, chemical, optical and electrical properties, TiO2 nanoparticles (NPs) are widely used in photocatalysis, electrochemistry, and production of cosmetics, pigments, and biomedicine. The performance of TiO2 NPs in all the aforementioned applications is predominantly influenced by their size. In nature it exists in several polymorphs; stable rutile, metastable anatase and brookite. Rutile phase is the only high refractive index phase of TiO2. Moreover, it has higher relative permittivity and ultraviolet ray absorption rate. The rutile TiO2 can generally be obtained by high-temperature calcination of anatase NPs. However, calcination undoubtedly leads to agglomeration and crystal growth, hence increasing particle size. So, fabrication of rutile titania NPs at low temperatures is of great importance. Here, ultra-small rutile TiO2 NPs of ~ 5 nm has been synthesized by developing a facile reproducible sol-microwave method at low temperature (150 °C). These rutile TiO2 NPs have shown no surface defects, such as trivalent titanium (Ti3+) ions and oxygen vacancies. The resulting samples were analyzed by the following methods: X-ray diffraction to determine the crystallinity and phase composition, Raman spectroscopy to refine the phase composition, X-ray Photoelectron Spectroscopy to identify oxidation states and phase composition in surface layers, and High-Resolution Transmission Electron Microscopy to study morphology, phase analysis, and surface quality assessment.
ACKNOWLEDGEMENT: The work was supported with the Czech Science Foundation, project No. 21-31852J and CzechNanoLab project LM2018110 funded by MEYS CR is gratefully acknowledged for the financial support of the measurements/sample fabrication at CEITEC Nano Research Infrastructure.