# Gram-Scale Synthesis and Optical Properties of Self-Trapped-Exciton-Emitting Two-Dimensional Tin Halide Perovskites

## TL;DR

This paper presents a new method to synthesize tin-based perovskite microcrystals that emit bright light and could be used in efficient white LEDs.

## Contribution

The first systematic study of luminescent properties in 2D tin halide perovskites and their application in high-efficiency white LEDs.

## Key findings

- ODASnBr4 microcrystals exhibit a PL peak at 567 nm and a PL QY of 99%.
- White LEDs using ODASnBr4 achieved a luminous efficacy of up to 96.27 lm/W.
- Luminescent differences between ODASnI4 and ODASnBr4 are attributed to light-driven ligand-to-metal charge transfer.

## Abstract

Lead halide perovskites (LHPs) have superior luminescent properties, but their toxicity hinders their commercialization, arousing interests in tin halide perovskites as environmentally friendly substitutes for LHPs. Herein, we synthesized a series of two-dimensional tin halide perovskite ODASnBr4-xIx (ODA denotes 1,8-octanediammonium, X = 0, 1, 2, 3, 4) microcrystals via an aqueous-phase method. The differences between ODASnI4 and ODASnBr4 in luminescent properties and morphological characteristics were systematically discussed for the first time and attributed to light-driven ligand-to-metal charge transfer. The prepared ODASnBr4 has a PL peak at 567 nm and a PL QY of 99%, and the white light-emitting diodes fabricated with ODASnBr4 and commercial blue phosphors realized a luminous efficacy of up to 96.27 lm/W, which demonstrated the remarkable potential of ODASnBr4 microcrystals for high-efficiency white light-emitting diode applications.