Large-scale facile-synthesis and bistable emissions of one-dimensional organic-inorganic CHNPbBr metal halide crystals with bipolaronic states

Low-dimensional metal halides have attracted much attention because of their excellent physical properties and potential application in optoelectronic field. Herein, we developed a novel facile method based on mechanochemical synthesis to prepare one-dimensional (1D) C 4 H 14 N 2 PbBr 4 (C 4 H 14 N 2 2+ : N , N ′-dimethylethylenediamine cation) micro-crystals on a large scale. This 1D structure enables the formation of self-trapped excited states that exhibit bluish white-light emission, and the photoluminescence quantum yield (PLQY) is about 18.4% under excitation of a 365 nm ultraviolet (UV) lamp. Interestingly, C 4 H 14 N 2 PbBr 4 exhibits an unusual bistable emission, i.e. , when excited by a 365 nm beam from a UV lamp, its emission occurs at about 461 nm, while excited by a 365 nm laser pulse, its emission maximum is located at 546 nm. The formation of self-trapped exciton (STE) pairs (bipolaron) via coupling of two adjacent PbBr 4 2− clusters by di-amine groups results in the bistable emission in the 1D chain. It is worth mentioning that the as-synthesized C 4 H 14 N 2 PbBr 4 has the advantages of high chemical, thermal and photostability, and large-scale manufacture along with remarkable photophysical properties, which provide a broad prospect for optoelectronic applications. One-dimensional C 4 H 14 N 2 PbBr 4 micro-crystals have been prepared by modified mechanochemical synthesis, which exhibit an unusual bistable emission.