High efficiency ETM-free perovskite cell composed of CuSCN and increasing gradient CH3NH3PbI3

Abstract

To enhance device performance and reduce fabrication cost, a series of electron transporting material (ETM)-free perovskite solar cells (PSCs) is developed by TCAD Atlas. The accuracy of the physical mode of PSCs is verified, due to the simulations of PEDOT:PSS–CH3NH3PbI3–PCBM and CuSCN–CH3NH3PbI3–PCBM p–i–n PSCs showing a good agreement with experimental results. Different hole transporting materials (HTMs) are selected and directly combined with n-CH3NH3PbI3, and the CuSCN–CH3NH3PbI3 is the best in these ETM-free PSCs. To further study the CuSCN–CH3NH3PbI3 PSC, the influences of back electrode material, gradient band gap, thickness, doping concentration, and bulk defect density on the performance are investigated. Energy band and distribution of electric field are utilized to optimize the design. As a result, the efficiency of CuSCN–CH3NH3PbI3 PSC is achieved to be 26.64%. This study provides the guideline for designing and improving the performances of ETM-free PSCs.