Tunable broad-band white-light emission in two-dimensional (110)-oriented lead bromide perovskite (C3H8N6)[PbBr4]: optical, electronic and luminescence properties

Abstract

Recently, room-temperature phosphorescence (RTP) in 2D hybrid perovskites has proved due to energy transfer from inorganic sheets to conjugated organic cations harnessing the triplet states. Thus far, only the sensitization of triplet states by inorganic excitons has been demonstrated. Herein, we report a novel (110)-oriented lead bromide perovskite, (C₃H₈N₆)PbBr₄ [abbreviated (H₂mela)PbBr₄], where within the inorganic sheets the self-trapped excitons generate broad-band emission and the Br⁻⋯π⁺ interactions harness the triplet excitons of organic components, via intersystem crossing (ISC), leading to dual fluorescence emission and RTP. To the best of our knowledge, based on the strategy of heavy-atom-participated anion–π⁺ interactions, the first RTP-active 2D-perovskite was successfully stabilized. The solid-state photoluminescence studies showed that the color rendering index (CRI) and chromaticity coordinates (x,y) as well as the correlated color temperature (CCT) of the white-light emission can be tuned via excitation energy variation. The emission of light varies from “cold” white light to “warm” white light by decreasing the excitation energy. When excited at 365 nm and 375 nm, our perovskite yielded “cold” white-light emission with the highest CRI of 97 and 99.