Using different chemical methods for deposition of CdS on TiO2 surface and investigation of their influences on the dye-sensitized solar cell performance

Chalcogenide phase change materials based on germanium-antimony-tellurides (GST-PCMs) have shown outstanding properties in non-volatile memory (NVM) technologies due to their high write and read speeds, reversible phase transition, high degree of scalability, low power consumption, good data retention, and multi-level storage capability. However, GST-based PCMs have shown recent promise in other domains, such as in spatial light modulation, beam steering, and neuromorphic computing. This paper reviews the progress in GST-based PCMs and methods for improving the performance within the context of new applications that have come to light in recent years.

https://www.mdpi.com/2076-3417/9/3/530/pdf

A Review of Germanium-Antimony-Telluride Phase Change Materials for Non-Volatile Memories and Optical Modulators

N-doped TiO2 thin films have been prepared by reactive RF magnetron sputtering at different pressures and with different compositions using a dual reactive gas mixture of nitrogen and oxygen. The morphological, optical, photo-electrochemical and photocatalytic properties have been studied in order to investigate the white light and visible light photoactivities of the films. Significant control over the band gap energy in the films was achieved by varying the deposition parameters. Photoelectrochemical characterization revealed improved white light photocurrent generation in nitrogen doped films prepared at low pressures. However, the visible light photocurrent generation showed improvement for all deposition pressures, and changed accordingly with the nitrogen incorporation. Photocatalytic measurements of a common chemical pollutant NMP (N-methyl-2-pyrrolidone) under different irradiation conditions provided evidence of improved photoactivity for samples prepared at high pressure, due to the increased active surface area and optimal nitrogen doping levels. Overall, this study showed a simple method to produce highly controllable nitrogen doping in different sites within TiO2 showing improved visible light photoactivity and photo induced pollutant degradation. More interestingly, by investigating the effect of different nitrogen sites in nitrogen doped TiO2, we have shown that the optimized conditions for photocatalysis do not correspond to those for water splitting.

Control of the visible and UV light water splitting and photocatalysis of nitrogen doped TiO2 thin films deposited by reactive magnetron sputtering

Optical properties of ZnO nanoparticles dispersed in PMMA/PVDF blend

Structure and optical analysis of Ta2O5 deposited on infrasil substrate

Cu2HgI4 powder has been prepared by precipitation from reactive chemical solutions. An electron beam gun evaporation system was used to deposit the prepared powder in a thin film form onto a Corning 7059 glass substrate. The x-ray diffraction study reveals that the as-deposited films are polycrystalline in nature and have a composition corresponding to the Cu2HgI4 single phase. The differential thermal analysis curve exhibits a strange endothermic peak located at a temperature of 355.5 K, corresponding to the phase change from the first-order phase to the fast ion-conducting phase. The phase change is accompanied by a colour change from bright-red (β-phase) to dark-brown (α-phase). The optical properties of as-deposited films have been calculated from the recorded transmission and reflection data in the spectral range 600–2500 nm. The refractive index of the as-deposited films was found to follow the two-term Cauchy dispersion relation and is adequately described by the effective-single-oscillator model. The refractive index–wavelength variation leads to the determination of the oscillator parameters Eo and Ed to be 3.113 and 9.883, respectively. The static refractive index, no(0), and static dielectric constant, es, were also calculated as a result of the latter data and were found to be 2.043 and 4.175, respectively. The analysis of the optical absorption coefficient confirmed the presence of a direct optical transition with a band gap energy of 1.96 eV.

https://iopscience.iop.org/article/10.1088/0022-3727/41/2/025311/pdf

W Z Soliman

Papers

Optical properties of thermochromic Cu2HgI4 thin films