Influence of Crystal Structure, Encapsulation, and Annealing on Photochromism in Nd Oxyhydride Thin Films
D. Chaykinab (TU Delft - ChemE/Materials for Energy Conversion and Storage)
F. Nafezarefi (TU Delft - ChemE/Materials for Energy Conversion and Storage)
G. Colombi (TU Delft - ChemE/Materials for Energy Conversion and Storage)
S Cornelius (TU Delft - ChemE/Materials for Energy Conversion and Storage)
Lars J. Bannenberg (TU Delft - RID/TS/Instrumenten groep)
Herman Schreuders (TU Delft - ChemE/O&O groep)
B. Dam (TU Delft - ChemE/Chemical Engineering)
More Info
expand_more
Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.
Abstract
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 from rapid oxidation, we add a thin ALD coating of Al2O3, which increases the lifetime of the films from 1 day to several months. Encapsulation of the films also influences photochromic bleaching, changing the time dependency from first-order kinetics. As well, the partial annealing which occurs during the ALD process results in a dramatically slower bleaching speed, revealing the importance of defects for the reversibility (bleaching speed) of photochromism.
help_outline