Amorphous tungsten trioxide films offer an interesting electrochromic system whose properties are readily amenable to study in a senior undergraduate laboratory. Basic optical color center properties, and electron and proton diffusion processes are characterized for the HxWO3 produced; additional experiments including the variation of the chemical potential of the hydrogen component and low‐temperature exploration of the metal‐insulator transition are proposed for the advanced student. The samples are easily prepared and measured by elementary means. The broad solid‐state concepts involved enrich standard advanced laboratory repertoires of more conventional nuclear and NMR experiments.

Topics
Phase transitions, Proton diffusion, Laboratory procedures, Crystallographic defects, Electrooptical effects, Nuclear magnetic resonance spectroscopy, Education
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© 1979 American Association of Physics Teachers.
1979
American Association of Physics Teachers
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