Intrinsic point defects in inorganic perovskite CsPbI₃ from first-principles prediction

Cubic inorganic perovskite CsPbI₃ is a direct bandgap semiconductor, which is promising for optoelectronic applications, such as solar cells, light emitting diodes, and lasers. The intrinsic defects in semiconductors play crucial roles in determining carrier conductivity, the efficiency of carrier recombination, and so on. However, the thermodynamic stability and intrinsic defect physics are still unclear for cubic CsPbI₃. By using the first-principles calculations, we study the thermodynamic process and find out that the window for CsPbI₃ growth is quite narrow and the concentration of Cs is important for cubic CsPbI₃ growth. Under Pb-rich conditions, V_Pb and V_I can pin the Fermi energy in the middle of the bandgap, which results in a low carrier concentration. Under Pb-poor conditions, V_Pb is the dominant defect and the material has a high concentration of hole carriers with a long lifetime. Our present work gives an insight view of the defect physics of cubic CsPbI₃ and will be beneficial for optoelectronic applications based on cubic CsPbI₃ and other analogous inorganic perovskites.