Theoretical Device Engineering for High‐Performance Perovskite Solar Cells Using CuSCN as Hole Transport Material Boost the Efficiency Above 25%

Abstract

Recently, perovskite solar cells (PSCs) have achieved remarkable power conversion efficiency (PCE) about 22.6%. While most of the hole transport materials (HTMs) used in PSCs are organic in nature with an issue of instability and high cost. In this paper, copper thiocyanate (CuSCN), a low cost inorganic HTM with excellent thermal and moisture stability, is applied as HTM for perovskite solar cells. The device modeling of PSCs is based on the device structure of FTO/TiO2/MAPbI3/CuSCN/Au. Two interface defect layers, IDL1 as electron transport material (ETM)/absorber interface and IDL2 as absorber/HTM interface, are introduced into the device model in order to study the impact of interface quality on the performance of PSCs. Among all of the parameters, defect density and conduction band offset (CBO) at ETM/absorber interface together with the defect density of absorber influence the device performance appreciably. Upon optimization of all of the parameters, PCE of the device approaches to 25.02%, which is very encouraging. The result shows that lead‐based PSC with CuSCN as HTM is an efficient system due to its enhanced hole transport, high electric conductivity, and improved chemical interaction with absorber. Further, defect density of ETM/absorber interface and absorber layer could be reduced by optimized deposition process.