将 Al₂(SO₄)₃ 水溶液作为电解质, 研究了磁控溅射制备的 WO₃ 薄膜的电致变色性能. Al₂(SO₄)₃水溶液的浓度范围为 0.025∼0.005 mol/L. 研究发现: 随着浓度的降低, 光调制略有增加, 响应时间延长, 着色效率 (coloration efficiency, CE) 略有降低; 降低 Al³⁺浓度可显著提高循环寿命; 在 0.005 mol/L 浓度下电荷密度保留度 R(Q) 和光学调制保留度 R(∆T )是 0.025 mol/L 浓度下的 3 倍以上; 在 0.005 mol/L Al₂(SO₄)₃ 水溶液中, WO₃薄膜的电致变色性能最佳, 光学调制率为 76.3%, CE 为 80.14 cm²/C, 着色响应时间/褪色响应时间为10.6 s/13.6 s, 具有长期循环稳定性 (200 次循环后的光学调制保留度为 102.7%). 电化学阻抗谱 (electrochemical impedance spectroscopy, EIS) 分析结果表明, 当电荷转移速率高于离子传质速率时, 有利于 WO₃ 薄膜电致变色循环的稳定.

The electrochromic performance of sputter-prepared WO₃ thin films with an Al₂(SO₄)₃  aqueous electrolyte was investigated. The concentration of Al₂(SO₄)₃  aqueous solution was varied from 0.025 to 0.005 mol/L. As the concentration decreased, the op-tical modulation increased slightly, the response time was prolonged, and the coloration efficiency (CE) decreased slightly. However, the cycle life was significantly increased by reducing the Al³⁺ concentration. The retentions of the charge density and optical modu-lation at a concentration of 0.005 mol/L were over three times those at 0.025 mol/L. The optimal electrochromic performance of the WO₃ thin films was observed in a 0.005 mol/L Al₂(SO₄)₃  aqueous solution, with high optical modulation of 76.3% and CE of 80.14 cm²/C; reasonable response time of 10.6 and 13.6 s for coloring and bleaching, respectively; and long-term stability (102.7% retention of optical modulation after 200 cycles). Electrochemical impedance spectroscopy (EIS) suggested that the charge-transfer rate exceeding the ion mass transfer rate was conducive to the stability of the electrochromic cycle of the WO₃ thin films.