Lead-free, luminescent perovskite nanocrystals obtained through ambient condition synthesis

TL;DR

This paper introduces a novel ambient-condition synthesis method for lead-free, luminescent perovskite nanocrystals, combining hot injection and ligand-assisted reprecipitation to produce stable, high-quality manganese-doped Cs₂NaBiCl₆ NCs at low temperatures.

Contribution

It presents a new low-temperature, ambient atmosphere synthesis route for lead-free perovskite nanocrystals using combined hot injection and ligand-assisted reprecipitation techniques.

Findings

Manganese doping enhances photoluminescence and quantum yield.

Room temperature synthesis yields emissive nanocrystals.

Nanocrystals exhibit excellent long-term ambient stability.

Abstract

Heterovalent substitution of toxic lead is an increasingly popular design strategy to obtain environmentally sustainable variants of the exciting material class of halide perovskites. Perovskite nanocrystals (NCs) obtained through solution-based methods exhibit exceedingly high optical quality. Unfortunately, most of these synthesis routes still require reaction under inert gas and at very high temperatures. Herein we present a novel synthesis routine for lead-free double perovskite NCs. We combine hot injection and ligand-assisted reprecipitation (LARP) methods to achieve a low-temperature and ambient atmosphere-based synthesis for manganese-doped Cs_{2}NaBiCl_{6} NCs. Mn incorporation is critical for the otherwise non-emissive material, with a 9:1 Bi:Mn precursor ratio maximizing the bright orange photoluminescence (PL) and quantum yield (QY). Higher temperatures slightly increased the material's performance, yet NCs synthesized at room temperature were still emissive, highlighting the versatility of the synthetic approach. Furthermore, the NCs show excellent long-term stability in ambient conditions, facilitating additional investigations and energy-related applications.