Amorphous and crystalline WO3films show electrochromic properties by means of double injection of cations and electrons. At low substrate temperature thermal evaporation technique produces an amorphous material mixed to a nanocrystalline phase. When this material is annealed at temperatures higher than 400 °C a fully crystalline structure is obtained. Different absorption mechanisms are responsible for colored amorphous and crystalline WO3layers, small polaron transitions and Drude-like free electron scattering, respectively. Furthermore, both O/W ratio and crystalline structure affect electrochromic efficiency of a WO3film. It has been confirmed that a hydrogen tungsten bronze structure appears when the material is colored. Finally, a self-bleaching process occurs when a colored WO3film is exposed to an oxidative environment.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Surfaces and Interfaces
- Surfaces, Coatings and Films
- Metals and Alloys
- Materials Chemistry
Antonaia, A., Polichetti, T., Addonizio, M. L., Aprea, S., Minarini, C., & Rubino, A. (1999). Structural and optical characterization of amorphous and crystalline evaporated WO. Thin Solid Films, 354(1), 73 - 81. https://doi.org/10.1016/S0040-6090(99)00567-2