Colloidal Synthesis of Strongly Fluorescent CsPbBr3 Nanowires with Width Tunable down to the Quantum Confinement Regime

TL;DR

This paper presents a colloidal synthesis method for CsPbBr3 nanowires with tunable widths from 20 nm to 3 nm, enabling control over quantum confinement and emission properties, with high photoluminescence efficiency.

Contribution

It introduces a novel synthesis approach for producing monodisperse, strongly fluorescent CsPbBr3 nanowires with tunable widths down to the quantum confinement regime.

Findings

Nanowires with widths from 20 nm to 3 nm were successfully synthesized.

Photoluminescence quantum yield increased from 12% to 77% with decreasing nanowire size.

Quantum confinement effects shifted emission from green to blue.

Abstract

We report the colloidal synthesis of strongly fluorescent CsPbBr3 perovskite nanowires (NWs) with rectangular section and with tuneable width, from 20 nm (exhibiting no quantum confinement, hence emitting in the green) down to around 3 nm (in the strong quan-tum-confinement regime, emitting in the blue), by introducing in the synthesis a short acid (octanoic acid or hexanoic acid) together with alkyl amines (octylamine and oleylamine). Temperatures below 70 {\deg}C promoted the formation of monodisperse, few unit cell thick NWs that were free from byproducts. The photoluminescence quantum yield of the NW samples went from 12% for non-confined NWs emitting at 524 nm to a maximum of 77% for the 5 nm diameter NWs emitting at 497 nm, down to 30% for the thinnest NWs (diameter ~ 3nm), in the latter sample most likely due to aggregation occurring in solution.