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

Abstract

We report the colloidal synthesis of strongly fluorescent CsPbBr3 perovskite\nnanowires (NWs) with rectangular section and with tuneable width, from 20 nm\n(exhibiting no quantum confinement, hence emitting in the green) down to around\n3 nm (in the strong quan-tum-confinement regime, emitting in the blue), by\nintroducing in the synthesis a short acid (octanoic acid or hexanoic acid)\ntogether with alkyl amines (octylamine and oleylamine). Temperatures below 70\n{\\deg}C promoted the formation of monodisperse, few unit cell thick NWs that\nwere free from byproducts. The photoluminescence quantum yield of the NW\nsamples went from 12% for non-confined NWs emitting at 524 nm to a maximum of\n77% for the 5 nm diameter NWs emitting at 497 nm, down to 30% for the thinnest\nNWs (diameter ~ 3nm), in the latter sample most likely due to aggregation\noccurring in solution.\n