New variants of (110)-oriented layered lead bromide perovskites, templated by formamidinium or pyrazolium

Abstract

Four new hybrid lead(II) halide perovskites, γ-(FA)2PbBr4, (FA)1.5(AA)0.5PbBr4, (PY)(GA)PbBr4 and (PY)(TZ)PbBr4 ((FA)=formamidinium, (AA)=acetamidinium, (PY)=pyrazolium, (GA)=guanidinium and (TZ)=1,2,3-triazolium), adopt (110)-oriented layered perovskite structures. While (PY) is found to template the formation of ‘conventional’ (110)-oriented structure types (i. e. containing staggered [PbBr4]∞ layers), (FA) is shown to facilitate formation of much less common variants based 3 : 1 ordering of the interlayer species or 3×2 step-like corrugation of the perovskite-like layers themselves.