The working mechanism of CsPbI₃/Sb₂S₃ heterojunction perovskite solar cells

Recently, significant breakthroughs in power conversion efficiencies (PCEs) have been obtained for 3D CsPbI3-based perovskite solar cells. In the present work, a novel heterojunction structure with 1D Sb2S3 as the hole transport layer was designed and investigated using solar cell capacitance simulator simulation software. The influence of thickness, band offset, conduction type, doping concentration, bulk and interface defect densities on the performances of the devices were analyzed. The PCE of the devices increases with the increase in the thicknesses of the CsPbI3 and Sb2S3 layers. The p-type conduction of the CsPbI3 under-layer has more advantages with regard to broadening of the doping density, and the higher acceptor density in the Sb(2)S(3 )over-layer contributes to the improvement of the performance of the device. In addition, the device performance is more sensitive to the defect density at the CsPbI3/Sb2S3 interface than that in the Sb2S3 over-layer. Finally, a PCE over 20% is obtained for the device with optimal parameters. These simulation results demonstrate the tremendous potential of a novel 3D/1D CsPbI3/Sb2S3 heterojunction design for high-performance and high-stability devices.