Core@Shell AgBr@CsPbBr3 Nanocrystals as Precursors to Hollow Lead Halide Perovskite Nanocubes

TL;DR

This paper presents a one-pot synthesis of core@shell AgBr@CsPbBr3 nanocubes that can be converted into hollow lead halide perovskite nanocubes with tunable optical properties, advancing nanocrystal fabrication techniques.

Contribution

It introduces a novel synthesis method for core@shell nanocrystals and demonstrates their transformation into hollow perovskite nanocubes with preserved optical features.

Findings

Successful synthesis of AgBr@CsPbBr3 nanocubes via one-pot method

Conversion to hollow CsPbI3, CsPbBr3, and CsPbCl3 nanocubes through halide exchange

Hollow nanocubes exhibit optical properties similar to solid counterparts

Abstract

We report the synthesis of colloidal core@shell AgBr@CsPbBr3 nanocubes by a one-pot approach, where the nucleation and growth of AgBr nanocrystals occurs rapidly after the injection of chemical precursors. This is immediately followed by the overgrowth of CsPbBr3, delivering AgBr@CsPbBr3 nanocubes of several tens of nanometers in size, with the volume of the AgBr core being only a small fraction of the overall nanocrystal volume. The formation of a core@shell geometry is facilitated by the epitaxial compatibility between AgBr and CsPbBr3 along multiple crystallographic directions. Exchange with Cl-ions leads to Ag@CsPbCl3 nanocubes, whereas exchange with I-ions leads to hollow CsPbI3 nanocubes, due to selective etching of the AgBr (or Ag) core region by the I-ions diffusing in the nanocubes. These hollow CsPbI3 nanocubes can then be converted into hollow CsPbBr3 and CsPbCl3 nanocubes by halide exchange. The optical emission properties of the hollow CsPbX3 (X=Cl, Br, I) nanocubes are in line with those expected from large, non-hollow halide perovskite nanocrystals, indicating that the small hollow region in the cubes has no major influence on their optical properties.