Brightly Luminescent CsPbBr3 Nanocrystals through Ultracentrifugation

Published

July 30, 2020

Author(s)

Jeffrey Fagan, Erik K. Hobbie, Aaron Forde, Richard D. Schaller, salim thomas, samuel brown, Matthew B. Kurtti, dmitri kilin

Abstract

Colloidal lead-halide-perovskite nanocrystals (NCs) offer broad color tunability with bright photoluminescence (PL), fast lifetime, and narrow spectral linewidth. Because emission is tuned primarily through chemical composition, quantum confinement and size-dependent optical effects have received relatively little attention. Using a combination of density-gradient and analytical ultracentrifugation, we study the photophysical profile of as-synthesized CsPbBr3 NC suspensions by separating them into size-resolved fractions. Size purification drastically alters the ligand profile of the parent suspensions, which necessitates post-processing through the addition of ligand and insoluble salt to achieve bright stable suspensions. We observe high PL quantum yield, blue-emitting fractions, and a narrowing of PL spectra, as well as a crossover from pure to stretched-exponential PL relaxation dynamics with decreasing NC size. As a function of edge length, L, the peak PL energy scales a L^-2, in agreement with the simple particle-in-a-box picture of quantum confinement.

Citation

Journal of Physical Chemistry Letters

Pub Type

Journals

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DOI Link

Keywords

perovskite, nanoparticle, separation, characterization

Citation

Fagan, J. , Hobbie, E. , Forde, A. , Schaller, R. , thomas, S. , brown, S. , Kurtti, M. and kilin, D. (2020), Brightly Luminescent CsPbBr3 Nanocrystals through Ultracentrifugation, Journal of Physical Chemistry Letters, [online], https://doi.org/10.1021/acs.jpclett.0c01936 (Accessed April 24, 2024)