PEG改性氧化钨薄膜的电致变色特性

doi:10.15541/jim20160273

摘要/Abstract

摘要：

为改善WO₃薄膜的电致变色性能, 采用溶胶-凝胶法制备了聚乙二醇(PEG)改性的WO₃电致变色薄膜, 并对其着色态与漂白态的光学特性以及循环伏安特性进行了研究。研究表明: PEG改性的WO₃薄膜具有良好的电致变色性能, 循环5000次伏安曲线无明显衰减, 对可见光的最大透过率调制幅度可达71%。PEG的加入改变了WO₃薄膜的微结构, 形成了平均直径为9 nm的介孔, 提高了离子在其中的扩散速率, 因此改善了WO₃薄膜的电致变色性能。由于循环稳定性对于电致变色材料的实际应用至关重要, 因此这种低成本的湿化学法有望用于制备高性能的WO₃基电致变色器件。

关键词: WO3薄膜, 电致变色, 溶胶-凝胶, 聚乙二醇改性

Abstract:

To improve the electrochromic properties of WO₃ thin films, polyethylene glycol (PEG)-modified WO₃ films via Sol-Gel method were prepared on indium-tin oxide (ITO) glass using dipping-coating technique with post annealing treatment in air. Crystal structures and morphologies of the as-prepared films were investigated by means of X-ray diffraction (XRD) and scanning electron microscope (SEM). Optical properties and cyclic voltage-current characteristic of the films were experimentally studied. Compared with the corresponding neat WO₃ films, the PEG-modified WO₃ films exhibit superior electrochromic properties, which possesses longer lifetime after 5000 cycles without obvious degradation, as well as higher optical modulation up to 71% at the wavelength of 633 nm. The results suggest that PEG addition in conjunction with post annealing treatment may change the micro-structure of WO₃ films to increase the electrochromic properties, due to the enhancement of ion diffusion capacity in the electrochromic material, as evident from the formation of the porous structure with an average pore diameter of 9 nm. As cycling stability is very crucial for practical applications of electrochromic materials, particularly for smart windows, this research provides a promising low-cost wet-chemical route to high performance WO₃-based electrochromic devices.

Key words: WO3 thin film, electrochromism, Sol-Gel, PEG-modified

中图分类号:

TQ174

路淑娟, 王唱, 赵博文, 汪浩, 刘晶冰, 严辉. PEG改性氧化钨薄膜的电致变色特性[J]. 无机材料学报, 2017, 32(2): 185-190.

LU Shu-Juan, WANG Chang, ZHAO Bo-Wen, WANG Hao, LIU Jing-Bing, YAN Hui. Electrochromic Properties of PEG-modified Tungsten Oxide Thin Films[J]. Journal of Inorganic Materials, 2017, 32(2): 185-190.

图/表 8

图1 ITO、W300和WP300样品的XRD图谱

Fig. 1 XRD patterns of ITO, W300, and WP300

图2 W300样品的SEM照片(a)、WP300样品不同放大倍数下的SEM照片(b, c)及其断面SEM照片(d)

Fig. 2 SEM images of W300 (a), different magnification SEM images of WP300 (b,c) and corresponding cross-sectional morphology (d)

图3 WO3薄膜(a)第一次循环和(b)第1000次循环的电化学循环伏安曲线

Fig. 3 First cycle (a) and 1000th cycle (b) cyclic voltammograms of the WO3 films

表1 WO3薄膜的电致变色性能

Table 1 Electrochemical properties of W300 and WP300 films

Sample	Anodic peak current density, i_p/(mA•cm^-2)	Diffusion coefficient D/(cm²•s^-1)	Reversibility K/%
W300	0.54	0.8×10^-10	61.3
WP300	2.24	13.53×10^-10	71.1

图4 WP300样品的电化学循环伏安曲线

Fig. 4 Cyclic voltammograms for the WP300 film

图5 W300样品和WP300样品在第1次(1th)第1000次(1000th)循环的原始态(O)褪色态(B)着色态(C)透过率曲线

Fig. 5 Transmittances of W300 and WP300 films in their original, bleached and colored stages after first and 1000th cycles

表2 WO3薄膜的透过率

Table 2 Transmittances of W300 and WP300 films

Sample	Original T/%	1th ΔT/%	1000th ΔT/%
W300	80.07	13	14.0
WP300	73.31	54	71.1

图6 不同循环次数下W300样品和WP300样品的ΔT对比

Fig. 6 ΔT of W300 and WP300 films under different cycle times

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