Effect of the addition of zirconium on the photochromic properties of yttrium oxy-hydride

Abstract

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 Y1-zZrzOxHy films with a small Zr cationic fractions (z < 0.15). At larger fractions the photochromic contrast is reduced. Zirconium is found to slow down the bleaching process, which suggests that the mobility of point defects may play a role in the thermal bleaching process. However, we cannot rule out substitution of zirconium in the YOxHy lattice which may also affect the photochromic properties.