Broadband White-Light Emission in One-Dimensional Organic-Inorganic Hybrid Silver Halide.

In the past few decades, organic-inorganic hybrid metal halides acting as single-component white light emission diodes (LEDs) have attracted extensive attentions, but most of the studies concentrate on the low-dimensional lead perovskites. Here, by using the nontoxic silver as optically active metal center, a series of hybrid silver halides based on one-dimensional structures were constructed and realized broadband white light emission. Compounds [H2DABCO][Ag2X4(DABCO)] (X = Br (1), I (2)) feature one-dimensional [Ag2X4(DABCO)]2- structures charged balanced by [H2DABCO]2+ cations. Compound 1 exhibits an efficient broadband white-light emission with photoluminescence quantum efficiency (PLQE) of about 2.1% and excellent photochemical stability, while compound 2 gives a broadband yellow-white emission centered at 556 nm. [HDABCO]3Ag5Cl8 (3) gives a strong broadband yellow emission (585 nm) with high PLQE of 6.7%, which can be easily fabricated as a white light emitting device. Based on the temperature-dependent, particle-size-dependent, and time-resolved PL measurements as well as other detailed studies, the broadband white-light emissions are ascribed to the synergetic effects of the organic and inorganic components. Our work provides a unique structural assembly method to explore lead-free single-component white-light illuminants from molecular level.

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.