Intrinsic defects at the interface of the FAPbI3/MAPbI3 superlattice: insight from first-principles calculations

Liping Cheng; Baoen Xu; Yanli Zeng; Lingpeng Meng

doi:10.1039/d2cp05114a

Intrinsic defects at the interface of the FAPbI₃/MAPbI₃ superlattice: insight from first-principles calculations

Phys Chem Chem Phys. 2023 Feb 22;25(8):6369-6379. doi: 10.1039/d2cp05114a.

Authors

Liping Cheng^{1

2}, Baoen Xu³, Yanli Zeng¹, Lingpeng Meng¹

Affiliations

¹ Hebei Key Laboratory of Inorganic Nano-materials, College of Chemistry and Materials Science, Hebei Normal University, Shijiazhuang 050024, P. R. China. yanlizeng@hebtu.edu.cn.
² College of Chemistry and Chemical Engineering, Xingtai University, Xingtai, 054001, P. R. China.
³ Technology Innovation Center of Hebei Province for Heterocyclic Compound, College of Chemical Engineering, Shijiazhuang University, Shijiazhuang 050035, P. R. China.

PMID: 36779360
DOI: 10.1039/d2cp05114a

Abstract

The use of a superlattice structure is an effective strategy to develop novel perovskites and obtain excellent light-absorbing materials. Based on first-principles calculations, we systematically studied the properties of intrinsic point defects at the interface of the FAPbI₃/MAPbI₃ superlattice. Our calculations show that charged defects are easier to form as compared to neutral ones at the superlattice interface due to low formation energies. Most defects with low formation energies have a shallow level in the band gap, and some deep level defects have high formation energies, so the superlattice perovskite exhibits high defect tolerance. Pb_I³⁺ is a dominant and detrimental defect, which acts as a non-radiative recombination center because it has low formation energy and a deep transition level. To avoid the generation of Pb_I³⁺ defects, it is suggested to synthesize FAPbI₃/MAPbI₃ superlattices under I-rich conditions. The calculated light absorption coefficients and photovoltaic performance parameters demonstrate that the presence of defects leads to a certain degree of reduction in light absorption and power conversion efficiency (PCE) of solar cells made of FAPbI₃/MAPbI₃ superlattices, but the excellent performance of the perovskite solar cell (PSC) is basically retained. The superlattice perovskites are still promising candidates for light-absorbing materials of PSCs. This study is expected to contribute to a better understanding of the properties of defects at the superlattice interface and provide theoretical support for the design of high performance PSCs.