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

Recently, two-dimensional (2D) organic-inorganic hybrid lead halide perovskites have attracted intensive attentions in solid state luminous fields as single-component white light emitters, and it is still significant to rationally optimize the photoluminescence (PL) performances through accurate structural design strategies. Herein, by carefully choosing homologous aliphatic amines as templates, we rationally designed two isotypical perovskites, [DMEDA]PbCl 4 ( 1 ) and [DMPDA]PbCl 4 ( 2 ), displaying tunable and stable broadband bluish white-light emission properties. Intriguingly, the subtle regulation on organic cations leads to higher distortion levels of 2D [PbCl 4 ] 2- layers and enhanced photoluminescence quantum efficiencies (PLQEs) (<1% for 1 and 4.9% for 2 ). The broadband light emissions can be ascribed to the self-trapped excitons (STEs) based on detailed studies of structural characterizations, time-resolved PL, temperature-dependent PL emissions, theoretical calculation and so on. This work gives a new guidance to rationally optimize the PL properties of low-dimensional halide perovskites and affords a platform to probe into the structure-property relationship.