Effect of interface defects on high efficient perovskite solar cells

Abstract In this paper, experimental J–V and external quantum efficiency (EQE) have been validated by the simulation model to show the improvement of the perovskite (PSK) solar cell (PSC) efficiency. The effect of interface properties at the electron transport layer (ETL) /PSK and PSK/hole transport layer (HTL) were examined with Solar Cell Capacitance Simulator (SCAPS). The interfaces between ETL/PSK/HTL were known as important factors for determining high open-circuit voltage (Voc) and FF. In this study, the impact of two kinds of interfaces, i.e., ETL/PSK and PSK/HTL, were examined. When the interface defect density at both interfaces decrease to 102 cm−2, the interface recombination became low, and Voc and FF increased. In contrast, when the trap defect energy at interfaces increased near to the bandgap of the PSK, the collection of photo-generated carriers was enhanced due to the formation of better offset for electron current flow. Thus, the optimum trap defect energy was 1.4 eV for both interfaces. Also, the capture cross-section for both electron and hole (σn and σp) was 10-20 cm2. These results will be useful for new material choice and optimization of ETLs and HTLs.