Program of Materials Science & Engineering, Convergence Institute of Biomedical Engineering and Biomaterials, Seoul National University of Science and Technology, Seoul 01811, Korea.
Nanoscale. 2017 Nov 23;9(45):17788-17793. doi: 10.1039/c7nr06796h.
In this study, mesoporous WO films with oxygen vacancy defects have been fabricated using the camphene-assisted sol-gel method. By controlling the optimized weight ratio of camphene on the WO films, we developed a unique film structure of the WO phase with both mesoporous morphology and oxygen vacancy defects due to the distinctive effect of camphene. The mesoporous WO films with oxygen vacancy defects fabricated using 10 wt% camphene showed superb multifunctional electrochromic (EC) properties with both fast switching speeds (5.8 s for coloration speed and 1.0 s for bleaching speed) and high coloration efficiency (CE, 51.4 cm C), which include the most prominent properties, particularly for switching speeds among WO-based films reported so far. The attractive EC properties are due to the synergistic effects of the mesoporous morphology and oxygen vacancy defects on the WO. The fast switching speeds are mainly caused by the reduced Li diffusion pathway due to the mesoporous morphology and increased electrical conductivity due to the oxygen vacancy defects. In addition, the increased CE value is due to the large transmittance modulation as a result of a more effective electrostatic contact of the mesoporous morphology and an increased optical bandgap of the oxygen vacancy defects on the WO. Therefore, this unique film structure of the mesoporous WO films with oxygen vacancy defects can be potentially regarded as a novel EC material for high-performance EC devices.
在这项研究中，采用莰烯辅助溶胶-凝胶法制备了具有氧空位缺陷的介孔 WO 薄膜。通过控制 WO 薄膜上莰烯的优化重量比，由于莰烯的独特作用，我们开发了一种具有介孔形态和氧空位缺陷的独特 WO 相薄膜结构。使用 10wt%莰烯制备的具有氧空位缺陷的介孔 WO 薄膜表现出优异的多功能电致变色（EC）性能，具有快速的变色速度（着色速度为 5.8s，褪色速度为 1.0s）和高的着色效率（CE，51.4cmC），其中包括迄今为止在 WO 基薄膜中报道的最突出的性能，特别是开关速度。吸引人的 EC 性能归因于 WO 上的介孔形态和氧空位缺陷的协同效应。快速的开关速度主要是由于介孔形态减小了 Li 扩散途径，以及氧空位缺陷增加了电导率。此外，CE 值的增加是由于介孔形态的更大的透射率调制以及 WO 上氧空位缺陷的光学带隙增加，从而导致更有效的静电接触。因此，这种具有氧空位缺陷的介孔 WO 薄膜的独特薄膜结构可以被视为高性能 EC 器件的新型 EC 材料。
