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Title: Promoting solution-phase superlattices of CsPbBr 3 nanocrystals
We present a size-selective method for purifying and isolating perovskite CsPbBr 3 nanocrystals (NCs) that preserves their as-synthesized surface chemistry and extremely high photoluminescence quantum yields (PLQYs). The isolation procedure is based on the stepwise evaporation of nonpolar co-solvents with high vapor pressure to promote precipitation of a size-selected product. As the sample fractions become more uniform in size, we observe that the NCs self-assemble into colloidally stable, solution-phase superlattices (SLs). Small angle X-ray scattering (SAXS) and dynamic light scattering (DLS) studies show that the solution-phase SLs contain 1000s of NCs per supercrystal in a simple cubic, face-to-face packing arrangement. The SLs also display systematically faster radiative decay dynamics and improved PLQYs, as well as unique spectral absorption features likely resulting from inter-particle electronic coupling effects. This study is the first demonstration of solution-phase CsPbBr 3 SLs and highlights their potential for achieving collective optoelectronic phenomena previously observed from solid-state assemblies.  more » « less
Award ID(s):
2131408
PAR ID:
10436719
Author(s) / Creator(s):
; ; ;
Publisher / Repository:
Nanoscale
Date Published:
Journal Name:
Nanoscale
Volume:
15
Issue:
22
ISSN:
2040-3364
Page Range / eLocation ID:
9728 to 9737
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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