Device simulation of a highly efficient CZTS solar cell with CuS as hole transport layer

Abstract

Earth abundant and economical chalcogenide Cu <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> ZnSnS <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf> (CZTS) is an encouraging active material for kesterite thin-film solar cell (TFSC) applications. However, the CZTS solar cell has drawback in performances compared to CIGS photovoltaic (PV) device due to insufficient current density and improper design. In the present work, the Solar Cell Capacitance Simulator in One Dimension (SCAPS-1D) is used to model a novel heterojunction CZTS solar cell and the PV performance parameters are also evaluated numerically. Herein, we have proposed the CuS material as a hole transport layer (HTL) at the back of CZTS absorber layer, the CdS as buffer layer, and the ITO as window layer, respectively. The simulation work is performed by investigating the effects of absorber thickness, carrier concentration, and defects on cell performances. The effect of temperature on device performances is also studied. With the heterojunction structure consisting of CuS/CZTS/CdS/ITO, the best conversion efficiency of 26.53% is achieved with open circuit voltage of 1.10 V, fill-factor of 87.28%, and short-circuit current density of 27.74 mA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The overall simulated results reveal that the CuS can be utilized as a prominent HTL to obtain the high efficiency in the CZTS TFSC with low-cost and reliable fabrication.