Abstract

A series of reversible photochromic nanocomposite materials based on WO₃ co-doped MoO₃ was prepared from deep eutectic solvent (DES) with water as co-solvent via a facile one-pot in-situ synthesis under ambient conditions. The nanocomposites were characterized by various techniques to ascertain the effect of different drying methods on the intrinsic morphology and photochromic responses of the materials. The FT-IR results show an interaction between the metal salts and DES. XRD patterns reveal monoclinic diffraction planes while TGA shows the thermal stability of the materials under all the drying methods at elevated temperatures. The SEM images reveal unevenly distributed and clustered prismatic-shaped crystallites which were confirmed with TEM. The vacuum-dried nanocomposite materials displayed an improved photochromic response with an instant visible color change from pale yellow to blue after 5 s of irradiation with UV-lamp, and further deepen after 300 s of irradiation. The reverse-bleaching process of the vacuum-dried nanocomposites was achieved under a dark condition in an oxygen environment for 90 min. The overall results show that drying methods may have an effect on the intrinsic morphology of nanocomposites but the vacuum drying method was the best, as the method reduces resistance to mass transfer with little or no effect on the microstructure in the material.

摘要

以水为共溶剂的深共晶溶剂（DES）通过简便的一锅法原位制备了一系列基于WO ₃共掺杂MoO _{3的可逆光致变色纳米复合材料}在环境条件下合成。通过各种技术对纳米复合材料进行表征，以确定不同干燥方法对材料固有形态和光致变色响应的影响。FT-IR 结果显示金属盐和 DES 之间存在相互作用。XRD 图案显示单斜衍射平面，而 TGA 显示材料在高温下所有干燥方法下的热稳定性。SEM 图像显示不均匀分布和成簇的棱柱形微晶，TEM 证实了这一点。真空干燥的纳米复合材料显示出改善的光致变色响应，在紫外灯照射 5 秒后，可见颜色立即从淡黄色变为蓝色，并在照射 300 秒后进一步加深。真空干燥纳米复合材料的反漂白过程是在黑暗条件下在氧气环境中进行 90 分钟。总体结果表明，干燥方法可能对纳米复合材料的固有形态有影响，但真空干燥方法是最好的，因为该方法降低了传质阻力，对材料的微观结构影响很小或没有影响。