Zheng Jin You, Liu Siyuan, Sun Qimeng, Guo Wenshuo, Qu Lingbo, Yu Xiaomei, Li Songjie
State Key Laboratory of Coking Coal Resources Green Exploitation, Engineering Research Center of Advanced Functional Material Manufacturing of Ministry of Education, School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, China.
School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, China.
Langmuir. 2025 Jul 29;41(29):19296-19308. doi: 10.1021/acs.langmuir.5c01695. Epub 2025 Jul 18.
Tungsten trioxide (WO) exhibits exceptional electrochromic properties, positioning it as a promising material for the fabrication of high-performance smart glass devices. Here, a two-step sol-gel approach was employed to synthesize crystalline/amorphous bismuth-doped WO (Bi-WO) nanoparticle composite films. The rationally designed composite film demonstrates superior electrochromic performance, featuring a high optical modulation of 82.7%, rapid switching times of 2.1 s for coloring and 2.0 s for bleaching, a prominent coloration efficiency of 102.23 cm/C at 630 nm, and remarkable cycling stability (retaining 84.5% of the initial optical modulation after 10,200 cycles). These improved properties are ascribed to the complementary advantages of the amorphous and crystalline Bi-WO layers as well as their interface synergy. Furthermore, the study investigates the phase transformation and morphological evolution accompanying performance degradation during continuous electrochromic cycling. Observations reveal that the film surface transitions from small-scale nanoparticles to anisotropic nanosheets, while the crystalline structure evolves from an amorphous state to the orthorhombic WO·HO. Notably, the open framework structure and reversible proton insertion/extraction behavior of the amorphous Bi-WO layer mitigate irreversible proton trapping, thereby maintaining long cycle stability. This work presents an effective strategy for constructing high-performance WO-based electrochromic composite materials by leveraging structural heterojunctions and interface engineering, providing insights into the design of next-generation smart optical devices.
三氧化钨（WO）具有卓越的电致变色性能，使其成为制造高性能智能玻璃器件的一种很有前景的材料。在此，采用两步溶胶-凝胶法合成了结晶/非晶态铋掺杂WO（Bi-WO）纳米颗粒复合薄膜。合理设计的复合薄膜展现出优异的电致变色性能，具有82.7%的高光调制率、2.1秒的快速着色切换时间和2.0秒的漂白切换时间、在630纳米处102.23厘米/库仑的显著着色效率以及出色的循环稳定性（在10200次循环后保留初始光调制的84.5%）。这些改进的性能归因于非晶态和结晶态Bi-WO层的互补优势及其界面协同作用。此外，该研究还探究了在连续电致变色循环过程中伴随性能退化的相变和形态演变。观察结果表明，薄膜表面从小尺寸纳米颗粒转变为各向异性纳米片，而晶体结构则从非晶态演变为正交晶系的WO·HO。值得注意的是，非晶态Bi-WO层的开放框架结构和可逆质子插入/提取行为减轻了不可逆质子捕获，从而保持了长循环稳定性。这项工作提出了一种通过利用结构异质结和界面工程构建高性能WO基电致变色复合材料的有效策略，为下一代智能光学器件的设计提供了见解。
