0‐D and 1‐D Perovskite‐like Hybrid Bismuth(III) Iodides

Abstract

AbstractLow‐dimensional hybrid bismuth halide perovskites have recently emerged as a class of non‐toxic alternative to lead perovskites with promising optoelectronic properties. Here, we report three hybrid bismuth(III)‐iodides: 0‐D (H2DAC)2Bi2I10 ⋅ 6H2O (H2DAC_Bi_I), 0‐D (H2DAF)4Bi2I10 ⋅ 2I3 ⋅ 2I ⋅ 6H2O (H2DAF_Bi_I), and 1‐D (H2DAP)BiI5 (H2DAP_Bi_I) (where H2DAC=trans‐1,4‐diammoniumcyclohexane; H2DAF=2,7‐diammoniumfluorene and H2DAP=1,5‐diammoniumpentane). Their synthesis, single‐crystal X‐ray structures, and photophysical properties are reported. The first two compounds comprise edge‐sharing [Bi2I10]4− dimers, while the last compound has cis‐corner‐sharing 1‐D chains of [BiI6]3− octahedra. Intercalation of triiodide (I3−) and iodide (I−) ions enhance electronic coupling between the [Bi2I10]4− of H2DAF_Bi_I, leading to enhanced optical absorption, compared to H2DAC_Bi_I which lacks such intercalants. Furthermore, calorimetric and variable temperature X‐ray diffraction measurements suggest a centrosymmetric to non‐centrosymmetric phase transition (monoclinic P212121↔orthorhombic Pnma) of H2DAP_Bi_I at 448 K (in heating step) and at 443 K (in cooling step).