Excellent p-type conductivity of β-CsPbI3 with defect Pb vacancy: First-principles

Due to the highest conversion efficiency of β-CsPbI3 among all the inorganic halide perovskite solar cells, it has attracted widespread attention. This paper systematically studies the formation energy and transition energy level of intrinsic point defects for β-CsPbI3 by using first-principles. The results demonstrate that growth of β-CsPbI3 is greatly affected by the Cs concentration and its growth window is extremely small. Although β-CsPbI3 has some deep-level defects, the formation energies of these defects are relatively high with positive values. Both under Pb-rich and Pb-poor conditions, the transitional energy levels of main intrinsic acceptor defect Pb vacancy (denoted as VPb) is in the valence band, which induces a high hole carrier concentration. Therefore β-CsPbI3 is considered as an excellent p-type semiconductor. It might be used to as a potential candidate of inorganic perovskite materials for solar cell absorber.