A new quaternary type IV deep eutectic solvent (DES) was prepared for the synthesis of WO₃/Nb₂O₅ complexes via a facile solvothermal route under ambient conditions. PXRD confirmed the formation of orthorhombic niobium tungsten oxide with semi-crystalline crystal phases. The SEM micrograph displayed a well aggregated and clustered particle distribution with irregular shapes, while TEM revealed a flower-shaped morphology of the materials. Furthermore, the UV-Vis measurements indicated electronic absorption in the range of 206–282 nm before irradiation with UV-light. After 5 s of irradiation, there was an instant color change from white to blue, which gradually deepened after 180 s. This color change was accompanied by a broad electronic absorption at 658 nm. Moreover, the intense photochromic material displayed fast fading within 20 min of exposure to the open air and remarkable recyclability. These observed properties could open new avenues for smart windows and color display devices.

中文翻译：

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四元IV型深共晶溶剂型氧化钨/氧化铌光致变色逆衰复合络合物

制备了一种新型四元IV型深共熔溶剂(DES)，用于合成WO ₃ /Nb ₂ O ₅配合物。环境条件下的一种简便的溶剂热途径。PXRD 证实了具有半结晶晶相的正交铌钨氧化物的形成。SEM 显微照片显示出具有不规则形状的良好聚集和聚集的颗粒分布，而 TEM 显示材料的花形形态。此外，UV-Vis 测量表明在用 UV 光照射之前在 206-282 nm 范围内的电子吸收。照射5 s后，颜色瞬间由白色变为蓝色，180 s后逐渐加深。这种颜色变化伴随着 658 nm 处的广泛电子吸收。此外，强烈的光致变色材料在暴露于露天 20 分钟内显示出快速褪色和显着的可回收性。