A new thin film photochromic material: Oxygen-containing yttrium hydride

• Published in: Solar energy materials and solar cells Vol. 95; no. 12; pp. 3596 - 3599
• Main Authors: Mongstad, Trygve, Platzer-Björkman, Charlotte, Maehlen, Jan Petter, Mooij, Lennard P.A., Pivak, Yevheniy, Dam, Bernard, Marstein, Erik S., Hauback, Bjørn C., Karazhanov, Smagul Zh
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.12.2011; Elsevier
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Engineering Science with specialization in Electronics; Exact sciences and technology; Hydrides; Hydrogen; Illumination; Infrared; Infrared radiation; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Photochromism; Photoconductivity; Physics; Solar cells; Solar energy; Sputter deposition; TECHNOLOGY; TEKNIKVETENSKAP; Teknisk fysik med inriktning mot elektronik; Thin films; Yttrium; Yttrium compounds; Thin films; Photochromism; Photoconductivity; Sputter deposition; Yttrium compounds; Hydrogen; Doped materials; Relaxation time; Thickness; Oxygen additions; Luminous intensity; Transparent thin film; Yttrium hydride; Ultraviolet radiation; Initial conditions; Optical transmission; Illumination; Trigger circuits; Photochromic materials
• DOI: 10.1016/j.solmat.2011.08.018
• ISSN: 0927-0248; 1879-3398

In this work we report on photochromism in transparent thin film samples of oxygen-containing yttrium hydride. Exposure to visible and ultraviolet (UV) light at moderate intensity triggers a decrease in the optical transmission of visible and infrared (IR) light. The photo-darkening is colour-neutral. We show that the optical transmission of samples of 500 nm thickness can be reduced by up to 50% after one hour of illumination with light of moderate intensity. The reaction is reversible and samples that are left in the dark return to the initial transparent state. The relaxation time in the dark depends on the temperature of the sample and the duration of the light exposure. The photochromic reaction takes place under ambient conditions in the as-deposited state of the thin-film samples. [Display omitted] ► Photochromic response in the as-deposited state at ambient conditions. ► Sensitive to visible and ultraviolet light. ► Colour-neutral photo-darkening. ► Persistent photoconductivity accompanies the photochromic darkening. ► Reversible reaction, material relaxes back to transparent state when left in dark.