Intrinsic point defects in inorganic perovskite CsPbI_3 from first-principles prediction

摘要

Cubic inorganic perovskite CsPbI_3 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 CsPbI_3. By using the first-principles calculations, we study the thermodynamic process and find out that the window for CsPbI_3 growth is quite narrow and the concentration of Cs is important for cubic CsPbI_3 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 CsPbI_3 and will be beneficial for optoelectronic applications based on cubic CsPbI_3 and other analogous inorganic perovskites.