Improving Broadband White-Light Emission Performances of 2D Perovskites by Subtly Regulating Organic Cations

Graphical Shining white : With the aim of optimizing the broadband white-light emission performance of low-dimensional perovskites, isomorphic 2D perovskites [DMEDA]PbCl 4 and [DMPDA]PbCl 4 were structurally designed on the basis of homologous amine templates. The subtle regulation of organic cations leads to increased distortion of the 2D [PbCl 4 ] 2− layers and enhancement of the photoluminescence quantum efficiency from <1 to 4.9 %. DMEDA: dimethylethylenediamine, DMPDA: N , N -dimethyl-1,3-diaminopropane. Recently, 2D organic–inorganic hybrid lead halide perovskites have attracted intensive attention in solid-state luminescence fields such as single-component white-light emitters, and rational optimization of the photoluminescence (PL) performance through accurate structural-design strategies is still significant. Herein, by carefully choosing homologous aliphatic amines as templates, isotypical perovskites [DMEDA]PbCl 4 ( 1 , DMEDA= N , N -dimethylethylenediamine) and [DMPDA]PbCl 4 ( 2 , DMPDA= N , N -dimethyl-1,3-diaminopropane) having tunable and stable broadband bluish white emission properties were rationally designed. The subtle regulation of organic cations leads to a higher degree of distortion of the 2D [PbCl 4 ] 2− layers and enhanced photoluminescence quantum efficiencies (<1 % for 1 and 4.9 % for 2 ). The broadband light emissions could be ascribed to self-trapped excitons on the basis of structural characterization, time-resolved PL, temperature-dependent PL emission, and theoretical calculations. This work gives a new guidance to rationally optimize the PL properties of low-dimensional halide perovskites and affords a platform to probe the structure–property relationship.