Ligand-Stabilized Reduced-Dimensionality Perovskites

Abstract
Metal halide perovskites have rapidly advanced thin film photovoltaic performance; as a result, the materials’ observed instabilities urgently require a solution. Using density functional theory (DFT), we show that a low energy of formation, exacerbated in the presence of humidity, explains the propensity of perovskites to decompose back into their precursors. We find, also using DFT, that intercalation of phenylethylammonium between perovskite layers introduces quantitatively appreciable van der Waals interactions; and these drive an increased formation energy and should therefore improve material stability. Here we report the reduced-dimensionality (quasi-2D) perovskite films that exhibit improved stability while retaining the high performance of conventional three-dimensional perovskites. Continuous tuning of the dimensionality, as assessed using photophysical studies, is achieved by the choice of stoichiometry in materials synthesis. We achieved the first certified hysteresis-free solar power conversion in a planar perovskite solar cell, obtaining a 15.3% certified PCE, and observe greatly improved performance longevity.

Citation
Ligand-Stabilized Reduced-Dimensionality Perovskites 2016 Journal of the American Chemical Society

Publisher
American Chemical Society (ACS)

Journal
Journal of the American Chemical Society

DOI
10.1021/jacs.5b11740

PubMed ID
26841130

Additional Links
http://pubs.acs.org/doi/abs/10.1021/jacs.5b11740

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