MODELING THE INFLUENCE OF CdS NANOWIRES ON THE PROPERTIES OF A SECOND-GENERATION PHOTOVOLTAIC CONVERTER

Abstract

The article investigates the influence of CdS nanowires on the characteristics of second-generation thin-film photovoltaic converters based on the ITO/SnO₂/nw-CdS/CdTe heterostructure. Modeling was performed using the SCAPS software, enabling the identification of optimal structural parameters to achieve maximum efficiency. The study highlights the use of a CdS nanowire layer as a buffer (window) layer, which provides enhanced optical properties and improves the fill factor and energy conversion efficiency. The modeling revealed that the optimal thickness of the CdTe absorber layer is 3 μm, the CdS buffer layer is 120 nm, and the SnO₂ conductive layer is 40 nm. For these parameters, the photovoltaic converter efficiency reaches 13.33%, with a fill factor of 77.39%. The application of CdS nanowires reduces carrier recombination at the layer interface, decreases light losses due to reflection, and enhances charge carrier transport. As a result, the spectral response of quantum efficiency improves, and the impact of defects on device performance diminishes. The effect of interface defect density at the nw-CdS/CdTe boundary was also studied. Results show that increasing the defect density beyond 1012 cm-2 significantly reduces the open-circuit voltage, short-circuit current, and thus the overall efficiency. It was established that interface defect states critically affect device parameters, emphasizing the importance of their control to enhance performance. The findings demonstrate the advantages of integrating CdS nanowires into thin-film solar cells based on the CdS/ CdTe heterojunction. This approach allows for achieving high efficiency and operational stability of solar cells, making them promising for large-scale production.