High Defect Tolerance in Lead Halide Perovskite CsPbBr₃

TLDR

The study investigates the formation energies and charge‑transition levels of intrinsic point defects in CsPbBr₃ using first‑principles calculations. First‑principles calculations reveal that defect tolerance arises from the absence of bonding–antibonding interactions between the conduction and valence bands. The results show that Br‑rich growth yields low defect formation energies, but avoiding Br‑rich conditions reduces defect concentrations; CsPbBr₃ remains highly defect‑tolerant with mostly shallow defect levels, preserving its electronic quality.

Abstract

The formation energies and charge-transition levels of intrinsic point defects in lead halide perovskite CsPbBr3 are studied from first-principles calculations. It is shown that the formation energy of dominant defect under Br-rich growth condition is much lower than that under moderate or Br-poor conditions. Thus avoiding the Br-rich condition can help to reduce the defect concentration. Interestingly, CsPbBr3 is found to be highly defect-tolerant in terms of its electronic structure. Most of the intrinsic defects induce shallow transition levels. Only a few defects with high formation energies can create deep transition levels. Therefore, CsPbBr3 can maintain its good electronic quality despite the presence of defects. Such defect tolerance feature can be attributed to the lacking of bonding-antibonding interaction between the conduction bands and valence bands.