A bismuth-based (III) hybrid perovskite as a highly air-stable, potential absorber with photoconductive response

Organic-inorganic hybrid perovskites materials (CH₃NH₃PbI₃) are recently great attention in the field of optoelectronic and photovoltaic devices. But, the stability and toxicity issues of the lead have seriously affected its commercial application. Here, we described a novel lead-free hybrid bismuth-based compound, [tert-butylammonium]₂ [Bi₂I₉] (TBI), which adopts a one-dimensional perovskite-like manner containing the corner-sharing BiI₆ octahedra structure. TBI displays outstanding light-absorbing properties with a gradual absorption edge at 632 nm, and optical bandgap of ∼1.96 eV which is lower than the bandgap of CH₃NH₃PbBr₃ and its semiconducting properties were steadily confirmed by the positive temperature-dependent conductivity along with the prominent photo-conductive responses in the range of (20 °C) 320–420 K (80 °C). In addition, TBI also shows brilliant phase stability from 1 day to 48 days in the open atmosphere, being much higher than CH₃NH₃PbI₃. This result suggests the potentials of TBI as the excellent absorber for photovoltaic and solar cell applications.