Single‐Component White‐Light Emission in 2D Hybrid Perovskites with Hybridized Halogen Atoms

With single‐component photoinduced white‐light (WL) emission, low‐dimensional hybrid halide perovskites have emerged as a new generation of luminescent materials; however, the effect of halogens on the intrinsic light emissions and the corresponding mechanisms is still unknown. Herein, the investigation of a family of two‐dimensional (2D) hybrid perovskites R 2 PbBr 4− x Cl x ( R = BA + , PMA + , PEA + ; x = 0, 1, 2, 3, 4) highlights the influence of halogens on intrinsic emission to reveal the dependence of the photoluminescence on the nature and contribution of the halogens. Ultrabroad emissions covering the entire visible‐light region are achieved in the halogen hybrid systems with the stoichiometry of R 2 PbBr 2 Cl 2 ( R = BA + , PMA + , PEA + ), showing their potential as single‐component WL phosphors in solid‐state lighting devices. The origin of the WL emissions is the synergistic recombination emission of free excitons and self‐trapped excitons. The ratio of halogens (Br/Cl) is confirmed to be a critical factor to fine‐tune the intrinsic emission properties. This work provides a feasible strategy to achieve single‐component WL emission in 2D hybrid perovskites, and proposes a method for regulating halogen contents for optimizing luminescent properties.