Design and optimization of WS2 based high performance double absorber solar cell

Abstract

Ultra-thin flexible photovoltaic materials for solar cells, like transition metal di-chalcogenides (TMDCs), hold significant promise due to their advantageous properties in photon absorption and electronic transport, being composed of atomically thin 2D layered semiconductor materials. An essential 2D-layered substance, tungsten Disulfide (WS2), classified as a TMDC, has garnered substantial attention due to its notable chemical and physical characteristics. This work presents a novel method for getting good photovoltaic results using WS2 solar cells. The suggested configuration ‘Al/FTO/SnS2/WS2/CuO/Ni’ comprises two absorber layers, which involves incorporating CuO as a supplementary absorber layer and SnS2 as the buffer layer. Several metals with varying work functions were investigated one at a time, therefore, Al and Ni were chosen for the front as well as back contact in order to produce a low resistance metal-semiconductor (M-S) interface. Additionally, aluminum (Al) and nickel (Ni), are commonly used due to their well-understood properties such as conductivity and thermal stability. Subsequently, an analysis was conducted to determine the effects of important influencing factors, such as operating temperature, layer thickness, defects density, and doping density of the absorber and buffer layers. The power conversion efficiency (PCE) was achieved approximately 30%, accompanied by an open circuit voltage (VOC) of 1.02 V, a short circuit current (JSC) of 34.35 mA cm−2, and a fill factor (FF) of 87.27%. This improvement was achieved by utilizing an Al/FTO/SnS2/WS2/CuO/Ni heterostructure. In comparison, the reference cell without CuO (single absorber) had a PCE of 21.74%, VOC of 0.88 V, JSC of 28.6 mA cm−2, and FF of 86.23%. The results obtained from an extensive numerical analysis and demonstrate the immense potential of the SnS2/WS2/CuO heterostructure, indicating a promising direction for the manufacturing of photovoltaic and photonic devices based on WS2-TMDCs. This study provides a systematic roadmap for the fabrication process as well as realization of low-cost high efficiency solar cell.