School of Electrical and Computer Engineering, RMIT University, Melbourne, VIC, Australia.
Nanoscale. 2012 Sep 28;4(19):5980-8. doi: 10.1039/c2nr31203d. Epub 2012 Aug 20.
We demonstrate that a three dimensional (3D) crystalline tungsten trioxide (WO(3)) nanoporous network, directly grown on a transparent conductive oxide (TCO) substrate, is a suitable working electrode material for high performance electrochromic devices. This nanostructure, with achievable thicknesses of up to 2 μm, is prepared at room temperature by the electrochemical anodization of a RF-sputtered tungsten film deposited on a fluoride doped tin oxide (FTO) conductive glass, under low applied anodic voltages and mild chemical dissolution conditions. For the crystalline nanoporous network with thicknesses ranging from 0.6 to 1 μm, impressive coloration efficiencies of up to 141.5 cm(2) C(-1) are achieved by applying a low coloration voltage of -0.25 V. It is also observed that there is no significant degradation of the electrochromic properties of the porous film after 2000 continuous coloration-bleaching cycles. The remarkable electrochromic characteristics of this crystalline and nanoporous WO(3) are mainly ascribed to the combination of a large surface area, facilitating increased intercalation of protons, as well as excellent continuous and directional paths for charge transfer and proton migration in the highly crystalline material.
我们证明，直接生长在透明导电氧化物（TCO）衬底上的三维（3D）结晶三氧化钨（WO3）纳米多孔网络是用于高性能电致变色器件的合适工作电极材料。这种纳米结构，其可达到的厚度可达 2μm，可以通过在氟掺杂氧化锡（FTO）导电玻璃上溅射沉积的 RF 溅射钨膜在室温下进行电化学阳极氧化来制备，施加的阳极电压低且化学溶解条件温和。对于厚度在 0.6 至 1μm 之间的结晶纳米多孔网络，通过施加低着色电压-0.25V，可实现高达 141.5cm2C-1的惊人着色效率。还观察到，多孔膜的电致变色性能在 2000 次连续着色-褪色循环后没有明显下降。这种结晶和纳米多孔 WO3 的显著电致变色特性主要归因于大表面积的结合，有利于增加质子的嵌入，以及在高结晶材料中电荷转移和质子迁移的优异连续和定向路径。
