Enhancement in oscillator strength of color centers in electrochromic thin films deposited from WO2powder
| Autor: | Kohei Kiyota, Masaki Watanabe, Tetsuzo Yoshimura, Yoshio Koike, Tanaka Masao |
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| Rok vydání: | 1982 |
| Předmět: | |
| Zdroj: | Journal of Applied Physics. 53:7314-7320 |
| ISSN: | 1089-7550 0021-8979 |
| DOI: | 10.1063/1.330139 |
| Popis: | Color centers in amorphous films evaporated from WO2 powder and WO3 powder were investigated. It was found that the device using ‘‘WO2’’ film, which has a WO3‐like structure, exhibits a high‐speed response and a high optical density, which is attributed to the enhancement in oscillator strength of the color centers in ‘‘WO2’’ films. The use of a configuration coordinate model revealed that the enhancement in the oscillator strength is caused by the increase in the degree of extension of the polaron wave function in the ‘‘WO2’’ film. The absorption band of the color center in ‘‘WO2’’ exhibits a low‐energy shift as compared with that in WO3, which supports the increase in the degree of the small polaron extension in ‘‘WO2.’’ We also studied the electrical conductivity, density, ir absorption spectra, and voltammograms of the ‘‘WO2’’ and WO3 films. These results suggest that the increase in the degree of the extension of the polaron wave function is caused by some change of the lattice condition which is int... |
| Databáze: | OpenAIRE |
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