Micron-size two-dimensional methylammonium lead halide perovskites

TL;DR

This paper presents a method to synthesize micron-sized 2D hybrid lead halide perovskite nanosheets with tunable thickness and lateral size, exhibiting high photoluminescent efficiency for optoelectronic applications.

Contribution

A novel hot-injection synthesis approach enabling precise control over 2D perovskite nanosheet size, thickness, and composition, with high quantum yields.

Findings

Lateral sizes from 0.05 to 8 microns achieved

Photoluminescent quantum yields up to 49%

Layered nanosheets with tunable n-stack structures

Abstract

Hybrid lead halide perovskites with 2D stacking structures have recently emerged as promising materials for optoelectronic applications. We report a method for growing 2D nanosheets of hybrid lead halide perovskites (I, Br and Cl), with tunable lateral sizes ranging from 0.05 to 8 microns, and a structure consisting of n stacked monolayers separated by long alkylamines, tunable from bulk down to n=1. The key to obtaining such a wide range of perovskite properties hinged on utilizing the respective lead halide nanosheets as precursors in a hot-injection synthesis that afforded careful control over all process parameters. The layered, quantum confined (n small than 4) nanosheets were comprised of major and minor fractions with differing n. Energy funneling from low to high n (high to low energy) regions within a single sheet, mediated by the length of the ligands between stacks, produced photoluminescent quantum yields as high as 49 percent. These large, tunable 2D nanosheets could serve as convenient platforms for future high efficiency optoelectronic devices.