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Chaykina, D. (author), Nafezarefi, F. (author), Colombi, G. (author), Cornelius, S. (author), Bannenberg, L.J. (author), Schreuders, H. (author), Dam, B. (author)Thin films of rare earth metal oxyhydrides show a photochromic effect, the precise mechanism of which is yet unknown. Here, we made thin films of NdH3-2xOx and show that we can change the band gap, crystal structure, and photochromic contrast by tuning the composition (O2-:H-) via the sputtering deposition pressure. To protect these films...journal article 2021
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Cornelius, S. (author), Colombi, G. (author), Nafezarefi, F. (author), Schreuders, H. (author), Heller, R. (author), Munnik, Frans (author), Dam, B. (author)Thin films of rare-earth (RE)-oxygen-hydrogen compounds prepared by reactive magnetron sputtering show a unique color-neutral photochromic effect at ambient conditions. While their optical properties have been studied extensively, the understanding of the relationship between photochromism, chemical composition, and structure is limited....journal article 2019
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Nafezarefi, F. (author), Cornelius, S. (author), Nijskens, J. (author), Schreuders, H. (author), Dam, B. (author)Thin films of yttrium oxy-hydride have interesting, reversible photochromic properties, the origin of which is poorly understood. To investigate the role of point defect mobility, we probed the effect of lattice contraction as induced by the addition of zirconium. Interestingly, we find no loss of photochromic contrast for Y <sub>1-z</sub>...journal article 2019
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Plokker, M.P. (author), Eijt, S.W.H. (author), Naziris, F. (author), Schut, H. (author), Nafezarefi, F. (author), Schreuders, H. (author), Cornelius, S. (author), Dam, B. (author)In order to investigate the mechanism of the photochromic effect in yttrium oxy-hydride (YO<sub>x</sub>H<sub>y</sub>) thin films, Doppler broadening positron annihilation spectroscopy (PAS) was applied to probe the electronic structure and the presence of vacancies in YO<sub>x</sub>H<sub>y</sub> and related materials as a function of...journal article 2018
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Nafezarefi, F. (author), Schreuders, H. (author), Dam, B. (author), Cornelius, S. (author)Recently, thin films of yttrium oxy-hydride (YO<sub>x</sub>H<sub>y</sub>) were reported to show an unusual color-neutral photochromic effect promising for application in smart windows. Our present work demonstrates that also oxy-hydrides based on Gd, Dy, and Er have photochromic properties and crystal structures similar to YO<sub>x</sub>H<sub...journal article 2017