Synthesis of Highly Photoluminescent All-Inorganic CsPbX3 Nanocrystals via Interfacial Anion Exchange Reactions

Zongtao Li,Binhai Yu,Kai Cao,Cunjiang Song,Yong Tang,Caiman Yan,Hanguang Lu,Xinrui Ding,Longshi Rao

doi:10.3390/nano9091296

Zongtao Li, Binhai Yu + Show 7 more

Open Access

https://doi.org/10.3390/nano9091296

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Abstract

All-inorganic cesium lead halide perovskite CsPbX3 (X = Cl, Br, I) nanocrystals (NCs) have attracted significant attention owing to their fascinating electronic and optical properties. However, researchers still face challenges to achieve highly stable and photoluminescent CsPbX3 NCs at room temperature by the direct-synthesis method. Herein, we synthesize CsPbX3 NCs by a facile and environmentally friendly method, which uses an aqueous solution of metal halides to react with Cs4PbBr6 NCs via interfacial anion exchange reactions and without applying any pretreatment. This method produces monodisperse and air-stable CsPbX3 NCs with tunable spectra covering the entire visible range, narrow photoluminescence emission bandwidth, and high photoluminescence quantum yield (PL QY, 80%). In addition, the chemical transformation mechanism between Cs4PbBr6 NCs and CsPbX3 NCs was investigated. The Cs4PbBr6 NCs were converted to CsPbBr3 NCs first by stripping CsBr, and then, the as-prepared CsPbBr3 NCs reacted with metal halides to form CsPbX3 NCs. This work takes advantage of the chemical transformation mechanism of Cs4PbBr6 NCs and provides an efficient and environmentally friendly way to synthesize CsPbX3 NCs.

Highlights

In recent years, all-inorganic cesium lead halide perovskite CsPbX3 (X = Cl, Br, and I) nanocrystals (NCs) have attracted a lot of attention due to their excellent properties, such as high photoluminescence (PL) quantum yield (QY), broad wavelength coverage, narrow PL emission bandwidth, and low trap state density [1,2,3,4]
All-inorganic cesium lead halide perovskite CsPbX3 (X = Cl, Br, and I) nanocrystals (NCs) have attracted a lot of attention due to their excellent properties, such as high photoluminescence (PL) quantum yield (QY), broad wavelength coverage, narrow PL emission bandwidth, and low trap state density [1,2,3,4]. These outstanding properties of CsPbX3 NCs distinguish them from traditional semiconductor NCs and make them promising candidates for various optoelectronic applications, including solar cells [5], lasers [6], photodetectors [7], and light emitting diodes (LEDs) [8]
Many methods have been developed for the synthesis of CsPbX3 NCs, such as hot-injection [9], solvothermal synthesis [10], post-treatment [11], ultrasonication [12], and mechanochemistry [13,14]

Summary

Introduction

All-inorganic cesium lead halide perovskite CsPbX3 (X = Cl, Br, and I) nanocrystals (NCs) have attracted a lot of attention due to their excellent properties, such as high photoluminescence (PL) quantum yield (QY), broad wavelength coverage, narrow PL emission bandwidth, and low trap state density [1,2,3,4]. The Akkerman group [17] treated pre-synthesized Cs4PbX6 NCs with excess PbX2 to synthesize green fluorescent CsPbX3 NCs. The Jing group [18] reported highly luminescent CsPbBr3 nanorods (NRs) through chemical transformation from Cs4PbBr6 NCs and tuned PL emission of the NRs over the full visible range through a halide anion-exchange reaction using hot-injection. We further demonstrated the potential applications of the perovskite NCs in white LED (WLEDs) by combining the green luminescent CsPbBr3 NCs with red luminescent CdSe NCs and a blue GaN LED chip, showing an encompassing 125% color gamut of the National Television System Committee (NTSC, 1913) standard

Chemicals and Materials

Preparation of Cs4PbX6 NCs

Conclusions