Unravelling Light‐Induced Degradation of Layered Perovskite Crystals and Design of Efficient Encapsulation for Improved Photostability |
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| Authors: | Hong‐Hua Fang Jie Yang Shuxia Tao Sampson Adjokatse Machteld E Kamminga Jianting Ye Graeme R Blake Jacky Even Maria Antonietta Loi |
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| Affiliation: | 1. Zernike Institute for Advanced Materials, University of Groningen, Groningen, the Netherlands;2. Center for Computational Energy Research, Department of Applied Physics, Eindhoven University of Technology, Eindhoven, the Netherlands;3. Fonctions Optiques pour les Technologies de l'Information, FOTON UMR 6082, CNRS, INSA de Rennes, Rennes, France |
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| Abstract: | Layered halide perovskites have recently shown extraordinary potential for low‐cost solution‐processable optoelectronic applications because of their superior moisture stability over their 3D counterparts. However, few studies have investigated the effect of light on layered hybrid perovskites. Here, the mechanically exfoliated nanoflakes of the 2D perovskite (PEA)2PbI4 (PEA, 2‐phenylethylammonium) are used as a model to investigate their intrinsic photostability. The light‐induced degradation of the flakes is investigated by using in situ techniques including confocal laser scanning microscopy, wide‐field fluorescence microscopy, and atomic force microscopy. Under resonant photoexcitation, (PEA)2PbI4 degrades to PbI2. It is clearly shown that this process is initiated at the crystal edges and from the surface. As a consequence, the photoluminescence of (PEA)2PbI4 is progressively quenched by surface traps. Importantly, the light‐induced degradation can be suppressed by encapsulation using hexagonal boron nitride (hBN) flakes and/or polycarbonates. This report sheds light on a specific mechanism of light‐induced degradation in layered perovskites and proposes a new encapsulation method to improve their photostability. |
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| Keywords: | 2D heterostructures encapsulation layered semiconductors photostability surface reactions |
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