Improving the performance of organic lead–tin laminated perovskite solar cells from the perspective of device simulation

The toxic lead in traditional perovskite solar cells (PSCs) poses a fatal threat to the environment, and it takes time and technology to complete the transition to lead-free perovskite solar cells. In this work, we introduce a lead–tin laminated perovskite solar cell, which can obviously reduce the toxicity of lead. Our ultimate goal is to study the factors that affect the performance of the device. On the basis of reducing the lead-based perovskite layer, use SACPS-1D (solar cell capacitor simulator) to optimize the parameters to maximize the performance of the entire device. Adjusting the physical parameters, we got the power conversion efficiency (PCE) of 17.59% and 6.14% for single-cell lead-based and single-cell tin-based perovskite solar cells respectively, which are close to the experimental results. The simulation results show that under the laminated structure, the thickness of the two perovskite absorber materials based on lead and tin has a certain influence on the performance of the device. After optimization, it is determined that the best thicknesses of lead-based absorption layer (LBA) and tin-based absorption layer (TBA) are 20 nm and 150 nm respectively. Optimize the doping concentration of acceptor and donor of the laminated perovskite absorber layer to obtain higher PCE and open circuit voltage ( V OC ). The best values are 10 15 cm −3 and 10 16 cm −3 for LBA and TBA respectively. We also found that when adjusting the positions of LBA and TBA, the recombination rate under different defect densities verified that the laminated absorption layer close to the light source side dominates the device performance. Provide reference for future optimization of laminated perovskite solar cells. Considering these factors comprehensively, we optimized the device performance parameters as follows: V OC = 0.93 V, J SC = 19.56 mA/cm 2 , FF = 71.12% and PCE = 12.89%.