Liang Lin, Zhang Jiajia, Zhou Yingying, Xie Junfeng, Zhang Xiaodong, Guan Meili, Pan Bicai, Xie Yi
Hefei National Laboratory for Physical Sciences at the Microscale, University of Science & Technology of China, Hefei, Anhui, PR China.
Sci Rep. 2013;3:1936. doi: 10.1038/srep01936.
Ultrathin nanosheets are considered as one kind of the most promising candidates for the fabrication of flexible electrochromic devices (ECDs) due to their permeable channels, high specific surface areas, and good contact with the substrate. Herein, we first report the synthesis of large-area nanosheets of tungsten oxide dihydrate (WO3·2H2O) with a thickness of only about 1.4 nm, showing much higher Li(+) diffusion coefficients than those of the bulk counterpart. The WO3·2H2O ultrathin nanosheets are successfully assembled into the electrode of flexible electrochromic device, which exhibits wide optical modulation, fast color-switching speed, high coloration efficiency, good cyclic stability and excellent flexibility. Moreover, the electrochromic mechanism of WO3·2H2O is further investigated by first-principle density functional theory (DFT) calculations, in which the relationship between structural features of ultrathin nanosheets and coloration/bleaching response speed is revealed.
超薄纳米片因其可渗透通道、高比表面积以及与基底的良好接触，被认为是制造柔性电致变色器件（ECD）最有前景的候选材料之一。在此，我们首次报道了合成大面积的二水合氧化钨（WO₃·2H₂O）纳米片，其厚度仅约1.4纳米，显示出比块状材料更高的Li⁺扩散系数。WO₃·2H₂O超薄纳米片成功组装到柔性电致变色器件的电极中，该器件表现出宽光学调制、快速颜色切换速度、高显色效率、良好的循环稳定性和优异的柔韧性。此外，通过第一性原理密度泛函理论（DFT）计算进一步研究了WO₃·2H₂O的电致变色机理，揭示了超薄纳米片的结构特征与显色/褪色响应速度之间的关系。
