Perovskite Quantum Dots Modeled Using ab Initio and Replica Exchange Molecular Dynamics

Andrei Buin, Riccardo Comin, Alexander H. Ip, Edward H. Sargent

Research output: Contribution to journalArticlepeer-review

21 Scopus citations

Abstract

© 2015 American Chemical Society. Organometal halide perovskites have recently attracted tremendous attention at both the experimental and theoretical levels. Much of this work has been dedicated to bulk material studies, yet recent experimental work has shown the formation of highly efficient quantum-confined nanocrystals with tunable band edges. Here we investigate perovskite quantum dots from theory, predicting an upper bound of the Bohr radius of 45 Å that agrees well with literature values. When the quantum dots are stoichiometric, they are trap-free and have nearly symmetric contributions to confinement from the valence and conduction bands. We further show that surface-associated conduction bandedge states in perovskite nanocrystals lie below the bulk states, which could explain the difference in Urbach tails between mesoporous and planar perovskite films. In addition to conventional molecular dynamics (MD), we implement an enhanced phase-space sampling algorithm, replica exchange molecular dynamics (REMD). We find that in simulation of methylammonium orientation and global minima, REMD outperforms conventional MD. To the best of our knowledge, this is the first REMD implementation for realistic-sized systems in the realm of DFT calculations.
Original languageEnglish (US)
Pages (from-to)13965-13971
Number of pages7
JournalThe Journal of Physical Chemistry C
Volume119
Issue number24
DOIs
StatePublished - Jun 8 2015
Externally publishedYes

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