Lead-Free Hybrid Indium Perovskites with Highly Efficient and Stable Green Light Emissions

Abstract

Lead halide perovskite nanocrystals (PNCs) have emerged as new-generation light-emitting materials with important potentials in optoelectronic applications. However, the toxicity of lead metal and the instabilities of PNCs overwhelmingly hinder their device engineering; thus, it is still urgent to construct new single crystalline lead-free perovskites with high-performance luminescent properties. Herein, we initially designed two novel crystalline hybrid indium chlorides, [DAPEDA]InCl6·Cl·H2O (1) and [DPA]3InCl6(2), containing discrete octahedral [InCl6]3-units. Remarkably, bulk crystals of 1 and 2 exhibited strong broadband green light emissions, derived from self-trapped excitons (STE) with high photoluminescence quantum yields (PLQYs) of 40% and 34%, respectively, with benefits from intrinsic quantumconfinement and highly localized electrons. More excitedly, the controlled Sb3+-doping strategy significantly boosted the emission efficiency with the highest PLQY of 89.2%. In addition, these indiumperovskites possessed ultrahigh structural and spectral stabilities in various extreme environments exceeding typical PNCs. Combined efficient and stable luminescent performances enable these indiumperovskites as excellent down-conversion green phosphors to successfully fabricate white lightemitting diodes with high color rendering index of 93. To the best of our knowledge, this work represents the first fabricated green light-emitting hybrid indium perovskites as excellent candidates for lead PNCs.