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Transfer of electrons or holes between localized states. Application to polymer electric conductivity
Král, Karel; Menšík, Miroslav
2017 - English
Basing on the quantum transport formalizm a formula for the irreversible transfer of charged particles has been introduced by us recently. This formula is expected to be suitable for the theoretical description of the electron or hole transfer between quantum dots, other nanoparticles, molecules, and so on. We discuss shortly the main physical properties of the formula. We also demonstrate the use of the formula for the theoretical analysis of the electronic physical properties of some electrically conductive polymers.\n
Keywords:
electron transfer; electron-phonon interaction; quantum nanostructures; transfer rate formula; polymer conductivity
Available at various institutes of the ASCR
Transfer of electrons or holes between localized states. Application to polymer electric conductivity
Basing on the quantum transport formalizm a formula for the irreversible transfer of charged particles has been introduced by us recently. This formula is expected to be suitable for the theoretical ...
The deposition of germanium nanoparticles on hydrogenated amorphous silicon
Stuchlík, Jiří; Volodin, V.A.; Shklyaev, A.A.; Stuchlíková, The-Ha; Ledinský, Martin; Čermák, Jan; Kupčík, Jaroslav; Fajgar, Radek; Mortet, Vincent; More Chevalier, Joris; Ashcheulov, Petr; Purkrt, Adam; Remeš, Zdeněk
2017 - English
We reveal the mechanism of Ge nanoparticles (NPs) formation on the surface of the hydrogenated amorphous silicon (a-Si:H) deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD) on ITO and a on boron doped nanocrystalline diamond (BDD). The coating of Ge NPs on a-Si:H was performed by molecular beam epitaxy (MBE) at temperatures up to 450 °C. The Ge NPs were characterized by Raman spectroscopy, scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). The nanocrystalline Ge particles are conglomerates of nanocrystals of size 10-15 nm and quantum dots (QDs) with size below 2 nm embedded in amorphous Ge phase. After coating with Ge NPs the a-Si:H thin films show better adhesion on BDD substrates then on ITO substrates.
Keywords:
Ge nanoparticles; a-Si:H; PECVD; MBE
Available at various institutes of the ASCR
The deposition of germanium nanoparticles on hydrogenated amorphous silicon
We reveal the mechanism of Ge nanoparticles (NPs) formation on the surface of the hydrogenated amorphous silicon (a-Si:H) deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD) on ITO and a on ...
Transparent boron-doped diamond electrode (t-BDDE) for spectroelectrochemistry
Lušpai, K.; Keszeliová, D.; Barlog, M.; Petrák, Václav
2017 - English
In this work we have studied the properties of high quality boron-doped diamond layers prepared on transparent substrate and their use as working electrode for EPR/UV-VIS-NIR spectroelectrochemistry. Final goal of this work is to benefit from the wide potential window of boron-doped diamond electrodes even in the field of the EPR/UV-VIS-NIR spectroelectrochemistry. The studied electrodes are compatiable with UV-VIS-NIR measurements. Spectral background is stable within the whole electrochemical window. Some of the electrodes, with lower doping level, are also compatible with EPR spectroscopy. In this work, the electrodes and their properties are presented and usability is demonstrate by the spectrochemistry on real sample.
Keywords:
boron-doped diamond electrode; spectroelectrochemistry; UV-VIS-NIR spectroscopy; EPR spectroscopy
Available at various institutes of the ASCR
Transparent boron-doped diamond electrode (t-BDDE) for spectroelectrochemistry
In this work we have studied the properties of high quality boron-doped diamond layers prepared on transparent substrate and their use as working electrode for EPR/UV-VIS-NIR spectroelectrochemistry. ...
Transparent boron-doped diamond electrode (t-BDDE) for spectroelectrochemistry
Lušpai, K.; Keszeliová, D.; Barlog, M.; Petrák, Václav
2017 - English
In this work we have studied the properties of high quality boron-doped diamond layers prepared on transparent substrate and their use as working electrode for EPR/UV-VIS-NIR spectroelectrochemistry. Final goal of this work is to benefit from the wide potential window of boron-doped diamond electrodes even in the field of the EPR/UV-VIS-NIR spectroelectrochemistry. The studied electrodes are compatiable with UV-VIS-NIR measurements. Spectral background is stable within the whole electrochemical window. Some of the electrodes, with lower doping level, are also compatible with EPR spectroscopy. In this work, the electrodes and their properties are presented and usability is demonstrate by the spectrochemistry on real sample.
Keywords:
boron-doped diamond electrode; spectroelectrochemistry; UV-VIS-NIR spectroscopy; EPR spectroscopy
Available at various institutes of the ASCR
Transparent boron-doped diamond electrode (t-BDDE) for spectroelectrochemistry
In this work we have studied the properties of high quality boron-doped diamond layers prepared on transparent substrate and their use as working electrode for EPR/UV-VIS-NIR spectroelectrochemistry. ...
Možnosti dělení keramických materiálů pulsním Nd:YAG laserem
Chmelíčková, Hana; Řiháková, L.
2017 - Czech
Příspěvek pojednává o optimalizaci procesu dělení keramických materiálů o tloušťce do 8 mm, konkrétně oxidové keramiky Al2O3, polykrystalického křemíku a slinuté dlaždice. Nd:YAG pulsní laser LASAG byl nastaven do konfigurace pro vrtání. V řadě experimentů byla zjišťována závislost hloubky řezu na rychlosti posuvů, procentu překrytí laserových stop a energii v pulsu. The paper deals with the optimization of the process of cutting of ceramic materials up to 8 mm thick, namely Al2O3 oxide, polycrystalline silicon and sintered tiles. Nd: YAG pulse Laser LASAG was set to drilling configuration. In a number of experiments, the depth of cut depth dependence on feed rate, laser overlay percentage, and pulse energy was determined.
Keywords:
laser cutting; drilling and welding; research; interaction with the material
Available at various institutes of the ASCR
Možnosti dělení keramických materiálů pulsním Nd:YAG laserem
Příspěvek pojednává o optimalizaci procesu dělení keramických materiálů o tloušťce do 8 mm, konkrétně oxidové keramiky Al2O3, polykrystalického křemíku a slinuté dlaždice. Nd:YAG pulsní laser LASAG ...
Back electrode influence on opto-electronic properties of organic photovoltaic blend characterized by Kelvin probe force microscopy
Čermák, Jan; Miliaieva, Daria; Hoppe, H.; Rezek, Bohuslav
2017 - English
Organic photovoltaic (PV) system consisting of P3HT:PCBM blend layer was prepared with an aluminum (Al) back electrode. After the final thermal annealing the Al layer was partially removed. Kelvin Probe Force Microscopy (KPFM) was used to measure photovoltage response to illumination by a solar spectrum light as a function of time (up to 3 weeks). Comparison of the same KPFM measurement on the areas with and without Al revealed differences in both morphology and photovoltage response to illumination. The data are discussed with view to reducing degradation of organic PV devices.\n
Keywords:
organic photovoltaics; Kelvin probe force microscopy; degradation
Available at various institutes of the ASCR
Back electrode influence on opto-electronic properties of organic photovoltaic blend characterized by Kelvin probe force microscopy
Organic photovoltaic (PV) system consisting of P3HT:PCBM blend layer was prepared with an aluminum (Al) back electrode. After the final thermal annealing the Al layer was partially removed. Kelvin ...
Preparing of the Chameleon coating by the Ion Jet Deposition method
Skocdopole, J.; Aversa, L.; Golan, Martin; Schenk, A.; Baldi, G.; Kratochvílová, Irena; Kalvoda, L.; Nozar, P.
2017 - English
Preparation of chameleon coatings using an Ionized Jet Deposition (IJD) technique is reported in the present paper. IJD is a new flexible method for thin film deposition developed by Noivion, Srl. The chameleon coatings are thin films characterised by a distinct change of their tribological properties according to the external conditions. The deposited films of SiC and TiN materials were examined by the Raman spectroscopy, SEM and XPS. The results of the Raman spectroscopy have proved an amorphous structure of SiC films. The data from XPS on TiN films have shown that the\nfilms are heavily oxidized, but also prove that the films are composed of TiN and pure Ti. The SEM provided information about the size of grains and particles constituting the deposited films, which is important for tribological properties of the films. Deposition of the chameleon coating is very complex problem and IJD could be ideal method for preparation of this coating.\n
Keywords:
Ion Jet Deposition; Chameleon coating; Raman spectroscopy; scanning electron microscope; X-ray photoelectron spectroscopy
Available at various institutes of the ASCR
Preparing of the Chameleon coating by the Ion Jet Deposition method
Preparation of chameleon coatings using an Ionized Jet Deposition (IJD) technique is reported in the present paper. IJD is a new flexible method for thin film deposition developed by Noivion, Srl. The ...
Plasma treatment impact on physical and chemical properties of polymeric fibers
Hlůžek, R.; Prošek, Z.; Trejbal, J.; Fládr, J.; Potocký, Štěpán
2017 - English
Presented work focuses on chemical and physical properties of plasma modified polymeric macro-fibers. Polyethylene terephthalate (PET) and polypropylene (PP) fibers having approx. 300 mu m in diameter were modified using cold oxygen plasma in order to achieve their surface changes needed for durable bond and adhesion with cement matrixes. A duration of plasma modification differed between 5 to 480 seconds, where an effect of the treatment was examined. Fiber surfaces chemical changes were researched via wettability measurement with demineralized water (the measurement was repeated immediately and after 1, 7 and 30 days to find out the changes stability). Physical changes were studied by means of weight balance (determination of weight loss) and tensile strength tests. It was found that wettability was enhanced significantly - up to two times, while mechanical properties of treated fibers decreased only slightly.\n
Keywords:
polymer macro-fibers; plasma treatment; wettability; tensile strength
Available at various institutes of the ASCR
Plasma treatment impact on physical and chemical properties of polymeric fibers
Presented work focuses on chemical and physical properties of plasma modified polymeric macro-fibers. Polyethylene terephthalate (PET) and polypropylene (PP) fibers having approx. 300 mu m in diameter ...
Spatially separated HOMO/LUMO at interface of polypyrrole physisorbed on oxidized nanodiamond facets
Matunová, Petra; Jirásek, Vít; Rezek, Bohuslav
2017 - English
Nanodiamond particles (NDs) have recently risen in popularity owing to their unique and perspective properties. Merging NDs with organic molecules, such as polypyrrole (PPy), into hybrid organic-semiconductor functional systems gives rise to potential applications in photovoltaics (PV), which is supported by prior experimentally observed charge transfer between bulk diamond and PPy. This work focuses on the most relevant (111) and (100) O-terminated ND facets with different coverage of surface terminating oxygens in ether, epoxide, ketone, and peroxide positions. We use density functional theory (DFT) computations employing B3LYP functional and 6-31G(d) basis set. Energetically the most favorable oxidized ND facets were further optimized with PPy in physisorbed configurations. Analysis of geometry, binding energy, HOMO-LUMO gap, and charge transfer was done on the relaxed PPy-ND structures. Multiple hydrogen bonds are formed between PPy amino groups and O atoms on ND surface.
Keywords:
diamond; naoparticules; polypyrrole; density functional theory; charge transfer
Available at various institutes of the ASCR
Spatially separated HOMO/LUMO at interface of polypyrrole physisorbed on oxidized nanodiamond facets
Nanodiamond particles (NDs) have recently risen in popularity owing to their unique and perspective properties. Merging NDs with organic molecules, such as polypyrrole (PPy), into hybrid ...
Surface acoustic waves in the layered systems
Tarasenko, Alexander; Boháč, Petr; Jastrabík, Lubomír
2016 - English
The laser acoustic method was used for analysis of two layered systems: thin titanium and diamond like carbon films both deposited on silicon. The film and substrate parameters are determined by fitting the theoretical curve to the measured dispersion curve. The fit software seeks that set of the system parameters whose theoretical curve coincides the best with the experimental data. For the titanium film the best root-mean square deviation was 2.04 m/s with the relative error < O.I % and for the DLC system the corresponding value was 0.30 m/s (the relative error < O.O1 % ).
Keywords:
laser acoustic method; surface acoustic waves; layered systems; Ti films; diamond-like carbon films
Available at various institutes of the ASCR
Surface acoustic waves in the layered systems
The laser acoustic method was used for analysis of two layered systems: thin titanium and diamond like carbon films both deposited on silicon. The film and substrate parameters are determined by ...
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