On the effect of atomic layer deposited Al2O3 on the environmental degradation of hybrid perovskite probed by positron annihilation spectroscopy

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Materials for optical and electronic devices, 2019, Vol.7 (18), p.5275-5284
• Main Authors: Dibyashree Koushik, Naziris, Frideriki, Melskens, Jimmy, Nusteling, Amber, Zardetto, Valerio, Schut, Henk, Kessels, Wilhelmus M M, Eijt, Stephan W H, Creatore, Mariadriana
• Format: Article
• Language: English
• Subjects: Aluminum oxide; Atomic layer epitaxy; Crystal defects; Crystal lattices; Crystallography; Defects; Degradation; Dependence; Depth profiling; Exposure; Film thickness; Grain boundaries; Lattice vacancies; Organic chemistry; Perovskites; Photoelectrons; Photovoltaic cells; Positron annihilation; Solar cells; Spectrum analysis; Thin films; Titanium dioxide; Water chemistry; X ray photoelectron spectroscopy; X-ray diffraction
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/c8tc06330c

The degradation of hybrid perovskite films when exposed to ambient air is a major challenge for the development of perovskite-based photovoltaics at large scale. At present, little is known about the environmental degradation of perovskite films associated with the development of structural defects or open volumes (such as atomic vacancies, voids, crystallographic defects and grain boundary defects) in the lattice, and about the depth dependence of the structural degradation. Therefore, in this work, we use Doppler broadening-positron annihilation spectroscopy (DB-PAS) depth-profiling to gain insight into the structural degradation of CH3NH3PbI3−xClx perovskite when exposed to ambient air. In parallel, we investigate the effect of ultrathin (