Controlling the nucleation and growth kinetics of lead halide perovskite quantum dots

Colloidal lead halide perovskite nanocrystals are of interest as photoluminescent quantum dots (QDs) whose properties depend on the size and shape. They are normally synthesized on subsecond time scales through hard-to-control ionic metathesis reactions. We report a room-temperature synthesis of monodisperse, isolable, spheroidal APbBr(3) QDs (A indicates cesium, formamidinium, and methylammonium) that are size tunable from 3 to >13 nanometers. The kinetics of both nucleation and growth are temporally separated and substantially slowed down by the intricate equilibrium between the precursor (PbBr2) and the A[PbBr3] solute, with the latter serving as a monomer. QDs of all these compositions exhibit up to four excitonic transitions in their linear absorption spectra, and we demonstrate that the size-dependent confinement energy for all transitions is independent of the A-site cation.

Automated summary

In this study, the authors report a room-temperature synthesis method for monodisperse, isolable, spheroidal APbBr3 QDs. By controlling the equilibrium between the precursor and the solute, as well as the kinetics of nucleation and growth, size tunable QDs were obtained.