Wang Junyi, Zhou Yurong, Zhao Wuxi, Niu Yutong, Mao Yuliang, Cheng Wei
Fujian Key Laboratory of Surface and Interface Engineering for High Performance Materials, College of Materials, Xiamen University, 422 Siming South Road, Xiamen, Fujian 361005, China.
Shenzhen Research Institute of Xiamen University, Shenzhen, Guangdong 518057, China.
ACS Appl Mater Interfaces. 2023 Feb 8;15(5):7120-7128. doi: 10.1021/acsami.2c20635. Epub 2023 Jan 30.
Near infrared (NIR) electrochromic (EC) devices that selectively modulate the NIR light without affecting the daylight represent a promising window technology for saving energy consumption of buildings. Current research efforts have been focused on developing NIR-EC materials, while little attention has been directed to the optically passive ion storage materials that are crucial for balancing charges in a full NIR-EC device. Herein, we report that amorphous phase mixed-vanadium-tungsten oxide films exhibit minimum optical change with high ion storage capacity, which enables the usage of the mixed-metal oxides as optically passive counter electrode materials for NIR-EC devices. The mixed-vanadium-tungsten oxide films are synthesized by a room-temperature solution-based photodeposition method that allows us to precisely engineer the metal compositions and thicknesses of the mixed-metal oxide films, thus optimizing their optical inertness and ion storage capability. A solid-state NIR-EC device assembled with the mixed-vanadium-tungsten oxide film as an ion storage layer and the amorphous tungsten oxide hydrate as the NIR-EC layer shows fast response speed with cycling stability up to 10,000 cycles, proving the outstanding charge balancing capability of mixed-metal oxide. Our work provides an efficient strategy for developing optically passive ion storage films with high ion storage capability for high-performance EC devices.
近红外（NIR）电致变色（EC）器件能够在不影响日光的情况下选择性地调制近红外光，是一种很有前景的建筑节能窗户技术。目前的研究工作主要集中在开发近红外电致变色材料上，而对于全近红外电致变色器件中电荷平衡至关重要的光学无源离子存储材料却很少关注。在此，我们报道非晶相混合钒钨氧化物薄膜具有最小的光学变化和高离子存储容量，这使得混合金属氧化物可作为近红外电致变色器件的光学无源对电极材料。混合钒钨氧化物薄膜是通过基于室温溶液的光沉积方法合成的，该方法使我们能够精确设计混合金属氧化物薄膜的金属成分和厚度，从而优化其光学惰性和离子存储能力。以混合钒钨氧化物薄膜作为离子存储层、非晶水合氧化钨作为近红外电致变色层组装的固态近红外电致变色器件显示出快速的响应速度，循环稳定性高达10000次循环，证明了混合金属氧化物出色的电荷平衡能力。我们的工作为开发具有高离子存储能力的光学无源离子存储薄膜以用于高性能电致变色器件提供了一种有效策略。
