Accession Number:

AD1105203

Title:

Water in Hybrid Perovskites: Bulk MAPbI3 Degradation via Super-Hydrous State

Personal Author(s):

Corporate Author:

PENNSYLVANIA UNIV PHILADELPHIA PHILADELPHIA United States

Report Date:

2019-04-11

Abstract:

Here, first-principles density functional theory calculations are presented which reveal how water incorporation in hybrid halide perovskiteCH3NH3PbI3 MAPbI3 catalyzes the phase transition to the CH3NH3PbI3.H2O edge-sharing monohydrate colorless phase, eliminatingits favorable photovoltaic properties. First, fundamental chemical and electrostatic interactions between water and each componentof MAPbI3 are analyzed, demonstrating their dependence on water concentration. Second, the energetics of incorporated water is explored,leading to the discovery of spontaneous phase segregation into dry regions and regions with more than one water per formula unittermedthe super-hydrous state. Third, the properties of the super-hydrous state are analyzed, including the acceleration of octahedron breaking andrearrangement by the high water density. This reveals the phase transformation to be a bulk process, initiated at the super-hydrous regions.This paper concludes with a discussion of how this super-hydrous model explains disparate recent experimental observations concerning thewater-induced transition from black perovskite to edge-sharing PbI2 yellow phase.

Descriptive Note:

Journal Article - Open Access

Supplementary Note:

APL Materials , 7, 01 Jan 0001, 01 Jan 0001, All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license(http://creativecommons.org/licenses/by/4.0/).

Pages:

0017

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Distribution Statement:

Approved For Public Release;

File Size:

12.27MB

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