Revealing the Role of Band Offsets on the Charge Carrier Dynamics of CsSn0.5Ge0.5I3‐Based Perovskite Solar Cell: A Theoretical Study

Abstract

A computational method using a unidimensional device simulator to theoretically study the CsSn0.5Ge0.5I3‐based perovskite solar cell (PSC) is adopted. The results provide a detailed understanding of energy level tuning between the transport and absorber layer in order to attain high‐performance parameters. The influence of band offset (BO) on the charge carrier dynamics of the PSCs is explained in terms of cliff and spike structures for various levels of conduction band offsets (CBOs) and valence band offsets (VBOs). The ideality factor (IF) is calculated with variable BOs, and its variation with the applied voltage is examined. IF value ranges from 1.95 to 1.55 and 1.57 to 1.51 for different levels of VBO and CBO, respectively. The study on absorber layer thickness is conducted at different levels of BOs, revealing the importance of optimized absorber thickness on the performance of the PSCs. The capacitance–voltage measurements under illumination and in the dark signify the importance of optimized BO on the built‐in potential and maximum capacitances of the PSC. The Nyquist plot of the PSC at different levels of BO reveals that the highest recombination resistance is obtained at the optimum BO levels, rendering device to attain superior performance.