Structural Diversity in Layered Hybrid Perovskites, A₂PbBr₄ or AA′PbBr₄, Templated by Small Disc-Shaped Amines

Abstract

We present three new hybrid layered lead(II) bromide perovskites of generic composition A₂PbBr₄ or AA'PbBr₄ that exhibit three distinct structure types. [TzH]₂PbBr₄ ([TzH⁺] = 1,2,4-triazolium) adopts a (001)-oriented layer structure and [AaH]₂PbBr₄, ([AaH⁺] = acetamidinium) adopts a (110)-oriented type, whereas [ImH][TzH]PbBr₄, ([ImH⁺] = imidazolium) adopts a rare (110)-oriented structure with enhanced corrugation (i.e., 3 × 3 type). The crystal structures of each are discussed in terms of the differing nature of the templating molecular species. Photoluminescent spectra for each are reported and the behaviors discussed in relation to the different structure of each composition.