Zero-Dimensional Hybrid Cd-Based Perovskites with Broadband Bluish White-Light Emissions.

Recently, low-dimensional organic-inorganic hybrid metal halide perovskites acting as single-component white-light emitting materials have attracted extensive attention, but most studies concentrate on hybrid lead perovskites. Herein, we present two isomorphic zero-dimensional (0D) hybrid cadmium perovskites, (HMEDA)CdX4 (HMEDA=hexamethylenediamine, X=Cl (1), Br (2)), which contain isolated [CdX4 ]2- anions separated by [HMEDA]2+ cations. Under UV light excitation, both compounds display broadband bluish white-light emission (515 nm for 1 and 445 nm for 2) covering the entire visible light spectrum with sufficient photophysical stabilities. Remarkably, compound 2 shows a high color rendering index (CRI) of 83 enabling it as a promising candidate for single-component WLED applications. Based on the temperature-dependent, powder-dependent and time-resolved PL measurements as well as other detailed studies, the broadband light emissions are attributed to self-trapped excitons stemming from the strong electron-phonon coupling.

Three-Dimensional Cuprous Lead Bromide Framework with Highly Efficient and Stable Blue Photoluminescence Emission.

Considering the instability and low photoluminescence quantum yield (PLQY) of blue-emitting perovskites, it is still challenging and attractive to construct single crystalline hybrid lead halides with highly stable and efficient blue light emission. Herein, by rationally introducing d10 transition metal into single lead halide as new structural building unit and optical emitting center, we prepared a bimetallic halide of [(NH4 )2 ]CuPbBr5 with new type of three-dimensional (3D) anionic framework. [(NH4 )2 ]CuPbBr5 exhibits strong band-edge blue emission (441 nm) with a high PLQY of 32 % upon excitation with UV light. Detailed photophysical studies indicate [(NH4 )2 ]CuPbBr5 also displays broadband red light emissions derived from self-trapped states. Furthermore, the 3D framework features high structural and optical stabilities at extreme environments during at least three years. To our best knowledge, this work represents the first 3D non-perovskite bimetallic halide with highly efficient and stable blue light emission.