Surface engineering for improved stability of CH3NH3PbBr3 perovskite nanocrystals

Organohalide perovskite nanocrystals (NCs) with a variety of nano-scale structures and morphologies have shown promising potential owing to their size- and composition-dependent optoelectronic properties. Despite extensive studies on their size-dependent optical properties, a lack of understanding o...

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Bibliographic Details
Published in:Nanoscale 2018-01, Vol.10 (4), p.1885-1891
Main Authors: Kirakosyan, Artavazd, Seokjin Yun, Soon-Gil, Yoon, Choi, Jihoon
Format: Article
Language:English
Subjects:
Morphology
Nanocrystals
Optical properties
Optoelectronics
Ostwald ripening
Photoluminescence
Physical properties
Steric hindrance
Surface stability
Surface treatment
Transformations
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Summary:Organohalide perovskite nanocrystals (NCs) with a variety of nano-scale structures and morphologies have shown promising potential owing to their size- and composition-dependent optoelectronic properties. Despite extensive studies on their size-dependent optical properties, a lack of understanding on their morphological transformation and the relevant stability issues limits a wide range of applications. Herein, we hypothesize a mechanism for the morphological transformation of perovskite NCs, which leads to dissolving NCs and forming microscale rectangular grains, resulting in a reduction of photoluminescence. We found that the morphological transformation from nanocrystal solids to microscale rectangular solids occurs via Ostwald ripening. A surface treatment with a surfactant suppresses the transformation, resulting in nearly monodisperse NCs with a square shape (∼20 nm edge size), and thus improves the stability of NC solution, as well as their photoluminescence performance and quantum yield (PLQY = 82%). Furthermore, we employed similar amine derivatives to investigate the effect of a molecular architecture (i.e. steric hindrance) on perovskite NC stability, which exhibited much enhanced PLQY (93%). These experimental results provide new insights into the fundamental relationship between the physical properties and the structure of perovskite nanocrystals required to understand their diverse optoelectronic properties.
ISSN:2040-3364
2040-3372
DOI:10.1039/c7nr06547g