Regulating structural asymmetry via fluorination engineering in hybrid lead bromide perovskites.

Abstract

Here, we synthesized a pair of chiral two-dimensional lead bromide perovskites R-/S-(C3H7NF3)2PbBr4 (1R/2S) using a H/F substitution strategy, which exhibit circular dichroism (CD) and circularly polarized luminescence (CPL) activity. Compared with one-dimensional non-centrosymmetric (C3H10N)3PbBr5 with local asymmetry obtained by isopropylamine, 1R/2S show a centrosymmetric inorganic layer despite the global chiral space group. Density functional theory calculations show that the formation energy of 1R/2S is lower than that of (C3H10N)3PbBr5, which implies the improved moisture stability in photophysical properties and CPL activity.