First-principles calculation analysis and photovoltaic properties of Cu compound-added perovskite solar cells

Abstract Experiments and first-principles calculations were performed to investigate the effects of Cu substitution in CH 3 NH 3 PbI 3 perovskite crystals. The first-principles calculations indicated that the energy level of the Cu d orbital formed above the VB maximum would be an acceptor or defect level. The effect of Cu addition on device properties was investigated, and the device with added 2% Cu provided higher efficiencies than the standard device. On the other hand, the decrease in short-circuit current density with increasing Cu content would be attributed to the defect level of the Cu d orbitals. First-principles calculations and experimental results provided insight into the function of Cu in CH 3 NH 3 -based perovskite crystals.