Gradient doping simulation of perovskite solar cells with CH3NH3Sn1_ xPbxI3 as the absorber layer

In this study, we built a perovskite solar cells(PSCs) model with a Au/CuSCN/CH3NH3Sn1_ xPbxI3/TiO2/FTO glass structure using the SCAPS program and use polynomial fitting to obtain the relationship between the conduction/valence bands of CH3NH3Sn1_ xPbxI3 and the x value, which is more complex and accurate than that in any previous research. The influences of thickness, electron and hole mobilities, relative permittivity, effective conduction band density, effective valence band density, and the value of x on the solar cell performance are analyzed. Furthermore, we simulate the situation where the doping concentration changes with the absorption layer depth of the device and a special bandgap is formed. The power conversion efficiency of the device im-proves from 19.96% to 20.52%, with an open-circuit voltage of 0.776 V, a short-circuit current of 33.79 mA/cm2, and a filling factor of 77.39% when double gradient doping is performed. The application value of gradient doping in the device absorption layer is obtained.