Numerical Simulation of a Graphene/N-ws2 Hit Solar Cell

Abstract

In this study, the WS2/a-Si:H/p-cSi heterojunction with intrinsic thin layer (HIT) solar cell structure was designed and simulated using the AFORS-HET software (version 2.5). Tungsten disulfide (WS2) stands out among two-dimensional materials due to its superior electrical and optical properties in photonic device applications. The optical and electronic properties of WS2 change as the thickness varies from bulk to monolayer. In this study, unlike other simulation studies on solar cells based on transition metal dichalcogenides in the literature, variation of the parameters such as the band gap, electron affinity, and refractive index with variation of the number of WS2 layers were taken into account. HIT solar cells are preferred among silicon-based solar cells due to their very high cell efficiencies. For this purpose, amorphous silicon (a-Si) was used as an interlayer. Additionally, graphene was used as the contact material due to its superior properties, and its performance was compared with ITO contacts. By optimizing the thicknesses and carrier concentrations of WS2, p-cSi, and the thickness of a-Si, a very high photovoltaic conversion efficiency of 29.64% was achieved. To the best of our knowledge, there is no study in the existing literature that investigates the integration of a WS2 layer in HIT solar cells. However, the findings of this study demonstrate that both the proposed device architecture and the WS2 material exhibit promising potential for future applications in optoelectronic technologies.