Polaron Self-localization in White-light Emitting Hybrid Perovskites

Abstract

Two-dimensional (2D) perovskites with general formula $APb{X}_4$ are attracting increasing interest as solution processable, white-light emissive materials. Recent studies have shown that their broadband emission is related to the formation of intra-gap color centers; however, the nature and dynamics of the emissive species have remained elusive. Here we show that the broadband photoluminescence of the 2D perovskites $(EDBE)PbC{l}_4$ and $(EDBE)PbB{r}_4$ stems from the localization of small polarons within the lattice distortion field. Using a combination of spectroscopic techniques and first-principles calculations, we infer the formation of ${P{b}_2}^{3+}$, $P{b}^{3+}$, and ${X_2}^{-}$ (where X=Cl or Br) species confined within the inorganic perovskite framework. Due to strong Coulombic interactions, these species retain their original excitonic character and form self-trapped polaron-excitons acting as radiative color centers. These findings are expected to be applicable to a broad class of white-light emitting perovskites with large polaron relaxation energy.

34 pages, 15 figures, 3 tables

References in corpus (2)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Lead Iodide Perovskite Light-Emitting Field-Effect Transistor

Cited by in corpus (1)

• Highly Luminescent Bulk Quantum Materials Based on Zero-Dimensional Organic Tin Halide Perovskites