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arXiv · 1610.08263

Synthesis of photochromic oxygen-containing yttrium hydride

J. Montero·F. A. Martinsen·M. Lelis·S. Zh. Karazhanov·B. C. Hauback·E. S. Marstein
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Abstract

Photochromic oxygen-containing yttrium hydride has been synthesized using a two step process. The process consists of an initial sputter deposition of oxygen-free yttrium hydride YH$_\mathrm{x}$, followed by a controlled reaction with air that causes incorporation of oxygen into the material. An in-situ study of the YH$_\mathrm{x}$ as it reacted with oxygen was made possible by applying an aluminium capping layer with a low but non-zero oxygen permeability prior to air exposure. During the reaction, the visual appearance of the YH$_\mathrm{x}$ went from dark and opaque to transparent and yellowish. This transition was accredited incorporation of oxygen into the material, as shown through analysis with energy dispersive x-ray spectroscopy (EDS) and x-ray photoemission spectroscopy (XPS). Grazing incidence x-ray diffraction (GIXRD) studies revealed an fcc structure both before and after oxygen exposure, with a lattice parameter that increased from 5.2 {\AA} to 5.4 {\AA} during the reaction. With the lattice parameter in the oxygen free YH$_\mathrm{x}$ being equal to that reported earlier for YH$_\mathrm{2}$, our findings suggest that the non-reacted YH$_\mathrm{x}$ in this study is in-fact YH$_\mathrm{2}$.

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J. Montero, F. A. Martinsen, M. Lelis, S. Zh. Karazhanov, B. C. Hauback, E. S. Marstein. 2016-10-26. Synthesis of photochromic oxygen-containing yttrium hydride. https://doi.org/10.1016/j.solmat.2017.02.001

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