Multi-Level Evaluation of UV Action upon Vitamin D Enhanced, Silver Doped Hydroxyapatite Thin Films Deposited on Titanium Substrate

Hydroxyapatite Ca10(PO4)6(OH)2 (HAp) is an important bioactive material for bone tissue reconstruction, due to its highly thermodynamic stability at a physiological pH without bio-resorption. In the present study, the Ag:HAp and the corresponding Ag:HAp + D3 thin films (~200 nm) coating were obtained by vacuum deposition method on Ti substrate. The obtained samples were exposed to different UV irradiation times, in order to investigate the UV light action upon thin films, before considering this method for the thin film’s decontamination. The effects of UV irradiation upon Ag:Hap + D3 are presented for the first time in the literature, marking a turning point for understanding the effect of UV light on composite biomaterial thin films. The UV irradiation induced an increase in the initial stages of surface roughness of Ag:HAp thin film, correlated with the modifications of XPS and FTIR signals. The characteristics of thin films measured by AFM (RMS) analysis corroborated with XPS and FTIR investigation highlighted a process of recovery of the thin film’s properties (e.g., RMS), suggesting a possible adaptation to UV irradiation. This process has been a stage to a more complicated UVA rapid degradation process. The antifungal assays demonstrated that all the investigated samples exhibited antifungal properties. Moreover, the cytotoxicity assays revealed that the HeLa cells morphology did not show any alterations after 24 h of incubation with the Ag:HAp and Ag:HAp + D3 thin films.

Two-step MAPbI3 deposition by Low-Vacuum Proximity-Space-Effusion for high-efficiency inverted semitransparent perovskite solar cells

Halide perovskite solar cells can combine high photoconversion efficiency with high transmittance. Herein, we developed an innovative vacuum deposition method to prepare CH3NH3PbI3 (MAPbI3) thin film for semitransparent perovskite solar...

Ag-TiO2 Assisted Photocatalytic Degradation of Cytostatic Drug Cyclophosphamide Under UV-VIS Light

Cyclophosphamide (CP) is a commonly prescribed cytostatic drug that has cytotoxic, genotoxic, mutagenic, carcinogenic and teratogenic effects on living organisms, which asks for its elimination from any water source. The photocatalytic degradation of CP under UV-VIS irradiation was studied, using non-doped TiO2 and Ag- doped TiO2 (0.5-1.7% wt.). The catalysts were synthesized by vacuum deposition method. The influence of Ag concentration on the degradation performance of CP was investigated and an optimal content of 1.0% Ag was established. Using of this catalyst assures the pollutant degradation with a rate constant kCP = 6.59 x 10-4 s-1 and an efficiency ηCP = 99% after120 min irradiation time. Based on the results of the quenching experiments in the presence of suitable scavengers, a mechanism of photocatalytic degradation of CP has been proposed. This consists in the attack of free hydroxyl radicals and superoxide radicals on the pollutant. Also, the contribution of Ag to inhibition of charge recombination and the additional generation of superoxide radicals, which are responsible for the higher photocatalytic activity of Ag doped TiO2 compared to non-doped TiO2, was emphasised.

Влияние водорода на оптическую прозрачность слоев палладия

The optical transparency of palladium layers within the wavelength region from 0.5 to 1.1 μm in air and in gaseous mixtures containing hydrogen in the range of 0.1 to 100 vol.% has been studied. The thermal-vacuum deposition method was used to prepare palladium layers on glass substrate. Buger’s law is implemented for layers thickness of order 450 Å. Pd layers of more than 1200 Å are damaged in 100% hydrogen medium. At some hydrogen concentration between 1-10 vol.% a sharp increase in Pd layer transparency is observed that is intrinsic for the first-order phase transition. The layer transparency change speed increases linearly with increasing the hydrogen concentration in gas medium.

Multiple strategies towards high-efficiency white organic light-emitting diodes by the vacuum deposition method

This review summarizes the progress in WOLEDs in recent years including all phosphorescent WOLEDs, hybrid WOLEDs, all fluorescence WOLEDs, doping-free WOLEDs, and single-emitter WOLEDs.

The Effect of the Indium(III) Phthalocyanine Chloride Films on the Behavior of Flexible Devices of Flat and Disperse Heterojunction

By means of flat-heterojunction structures based on small semiconductor molecules (MSCs), an analysis of the indium(III) phthalocyanine chloride (In(III)PcCl) film as a constituent of optoelectronic devices was performed. The study included the behavior of In(III)PcCl playing three different roles: a donor species, an electronic acceptor, and a hole layer carrier. The flat-heterojunction structures were prepared by vacuum deposition method that permits a controlled layer-by-layer growth of high purity films. The investigated structures were characterized by scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDS), UV-vis spectroscopy and optical bandgaps were obtained by Tauc’s and Cody’s methods. As the structures exhibit a large spectral absorption in the visible range, they were incorporated into flat-heterojunction devices based on flexible and rigid substrates. However, during the synthesis of those structures, the disperse heterojunction arrangement was found and indeed it showed to be more efficient than the initial flat-heterojunction. In order to complement these results, disperse heterojunction arrangement structure as well as its bandgap value were obtained by DFT calculations. Finally, the electronic behavior of both fabricated devices, disperse heterojunction and flat-heterojunction were compared.

Obtaining memristor elements based on non-noble materials

This study is aimed at creating memristor elements based on TiO2/TiOx layers with electrodes that do not contain noble and rare-earth metals, by vacuum deposition method. The characteristics of these elements analyzed by voltammetric methods show that the appearance of an N-type region of negative differential resistance on the current–voltage curve can be caused only by metal electrodes whose vacuum work function exceeds that of TiO2. The appearance of the N-type region on the current–voltage curve of a memristor element is possible only after electrically assisted vacuum forming. Mo–TiO2/TiOx–Ni/Cu structures, for which the ILR/IHR ratio reaches two orders of magnitude at a voltage of less than 4 V, have the most stable parameters.