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Tungsten oxide (WOx) thin films were synthesized through the RF magnetron sputtering method by varying the sputtering power from 30 W to 80 W. Different investigations have been conducted to evaluate the variation in different morphological, optical, and dielectric properties with the sputtering power and prove the possibility of using WOx in optoelectronic applications. An Energy Dispersive X-ray (EDX), stylus profilometer, and atomic force microscope (AFM) have been used to investigate the dependency of morphological properties on sputtering power. Transmittance, absorbance, and reflectance of the films, investigated by Ultraviolet-Visible (UV-Vis) spectroscopy, have allowed for further determination of some necessary parameters, such as absorption coefficient, penetration depth, optical band energy gap, refractive index, extinction coefficient, dielectric parameters, a few types of loss parameters, etc. Variations in these parameters with the incident light spectrum have been closely analyzed. Some important parameters such as transmittance (above 80%), optical band energy gap (~3.7 eV), and refractive index (~2) ensure that as-grown WOx films can be used in some optoelectronic applications, mainly in photovoltaic research. Furthermore, strong dependencies of all evaluated parameters on the sputtering power were found, which are to be of great use for developing the films with the required properties. [ABSTRACT FROM AUTHOR]

CuCl2 solutions of various molarities were used to treat CdSe thin films produced by RF magnetron sputtering. In-depth investigation on the impacts of this treatment on CdSe thin films were studied. The structural investigation revealed that all as-grown films exhibited the hexagonal phase peak at the (101) plane. The crystalline and grain sizes increased with CuCl2 treatment, reaching 114 nm for 0.1 M CuCl2-treated CdSe thin film. A granule-like morphology was seen on the treated films. Opto-electric study revealed that CuCl2 treatment improved CdSe film properties and tailored structural restrictions. The 0.30 M CuCl2 treatment was shown to be an important process parameter for the CdSe thin films, indicating its potential as a photovoltaic material. [ABSTRACT FROM AUTHOR]

In this study, tungsten di-sulphide (WS2), one of these key transition-metal dichalcogenide (TMDC) materials, is used as solar cell absorber material with a suitable solar cell configuration and analyzed by SCAPS-1D. Other main focuses include optimum absorber layer thickness, suitable material for buffer layer instead of CdS and effect of operating temperature on solar cell performance. An efficiency of 19.48% (with Voc of 0.90 V, Jsc of 24.94 mA/cm² and fill factor of 0.86) has been found for the cell with CdS based buffer layer. High efficiency WS2 solar cells have the optimized absorber thickness in the range of 2 µm to 3 µm. Moreover, the desired thickness of the buffer layer is observed in between 40-60 nm. Among different types (ZnO, ZnSe, ZnS, CdS and In2S3) of buffer layers, ZnO based WS2 solar cell shows the potential to reach out the highest efficiency of 25.71%. However, cell with ZnO buffer layer shows a temperature gradient of -0.24%/K. All these simulation results provide significant hints that may lead to higher efficiency of WS2 solar cells with beneficial experimental studies in practical implementation. [ABSTRACT FROM AUTHOR]

An ideal n-i-p perovskite solar cell employing a Pb free CH3NH3SnI3 absorber layer was suggested and modelled. A comparative study for different electron transport materials has been performed for three devices keeping CuO hole transport material (HTL) constant. SCAPS-1D numerical simulator is used to quantify the effects of amphoteric defect based on CH3NH3SnI3 absorber layer and the interface characteristics of both the electron transport layer (ETL) and hole transport layer (HTL). The study demonstrates that amphoteric defects in the absorber layer impact device performance significantly more than interface defects (IDL). The cell performed best at room temperature. Due to a reduction in Voc, PCE decreases with temperature. Defect tolerance limit for IL1 is 1013 cm−3, 1016 cm−3 and 1012 cm−3 for structures 1, 2 and 3 respectively. The defect tolerance limit for IL2 is 1014 cm−3. With the proposed device structure FTO/PCBM/CH3NH3SnI3/CuO shows the maximum efficiency of 25.45% (Voc = 0.97 V, Jsc = 35.19 mA/cm2, FF = 74.38%), for the structure FTO/TiO2/CH3NH3SnI3/CuO the best PCE is obtained 26.92% (Voc = 0.99 V, Jsc = 36.81 mA/cm2, FF = 73.80%) and device structure of FTO/WO3/CH3NH3SnI3/CuO gives the maximum efficiency 24.57% (Voc = 0.90 V, Jsc = 36.73 mA/cm2, FF = 74.93%) under optimum conditions. Compared to others, the FTO/TiO2/CH3NH3SnI3/CuO system provides better performance and better defect tolerance capacity. [ABSTRACT FROM AUTHOR]