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arXiv · 2004.08310

Composition, Size, and Surface Functionalization dependent Optical Properties of Lead Bromide Perovskite Nanocrystals

Palvasha Ijaz·Muhammad Imran·Márcio M. Soares·Hélio C. N. Tolentino·Beatriz Martín-García·Cinzia Giannini·Iwan Moreels·Liberato Manna·Roman Krahne
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Abstract

The photoluminescence (PL), color purity, and stability of lead halide perovskite nanocrystals depend critically on the surface passivation. We present a study on the temperature dependent PL and PL decay dynamics of lead bromide perovskite nanocrystals characterized by different types of A cations, surface ligands, and nanocrystal sizes. Throughout, we observe a single emission peak from cryogenic to ambient temperature. The PL decay dynamics are dominated by the surface passivation, and a post-synthesis ligand exchange with a quaternary ammonium bromide (QAB) results in a more stable passivation over a larger temperature range. The PL intensity is highest from 50K-250K, which indicates that the ligand binding competes with the thermal energy at ambient temperature. Despite the favorable PL dynamics of nanocrystals passivated with QAB ligands (monoexponential PL decay over a large temperature range, increased PL intensity and stability), the surface passivation still needs improvement toward increased emission intensity in nanocrystal films.

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Palvasha Ijaz, Muhammad Imran, Márcio M. Soares, Hélio C. N. Tolentino, Beatriz Martín-García, Cinzia Giannini, Iwan Moreels, Liberato Manna, Roman Krahne. 2020-04-17. Composition, Size, and Surface Functionalization dependent Optical Properties of Lead Bromide Perovskite Nanocrystals. https://doi.org/10.1021/acs.jpclett.0c00266

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