Numerical prediction on the photovoltaic performance of CZTS‐based thin film solar cell

Abstract

This article presents an enormously effective Cu 2 ZnSnS 4 (CZTS)‐based n ‐ZnS/ p ‐CZTS/ p + ‐WSe 2 thin film solar cell. The device has been studied by varying the thickness, doping concentration and defect density of each layer utilizing SCAPS‐1D simulation software. The power conversion efficiency (PCE) for n ‐ZnS/ p ‐CZTS single heterojunction is 14.06% with the J SC  = 20.26 mA cm −2 , V OC  = 0.88 V and FF = 78.59%, respectively. This PCE is elevated to 27.31% with the J SC  = 33.72 mA cm −2 , V OC  = 0.97 V and FF = 83.75%, respectively due to insertion of WSe 2 back surface field (BSF) layer in the same structure. The significant improvement of PCE mainly depends on short circuit current which is resulted due to WSe 2 layer that absorbs sub‐band gap photons through tail‐states‐assisted (TSA) photon upconversion method. These entire results demonstrate the potential of WSe 2 as BSF layer in CZTS‐based thin film solar cells.