Ahmed Sharjeel, Macharia Daniel K, Zhu Bo, Ren Xiaoling, Yu Nuo, Chen Liyun, Chen Zhigang
State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, International Joint Laboratory for Advanced Fiber and Low-dimension Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China.
Nanoscale. 2020 May 14;12(18):10335-10346. doi: 10.1039/c9nr10180b.
Photoreversible color switching systems (PCSSs) have attracted increasing attention in various applications, but in most PCSSs the discoloration process usually relies on harmful UV light as a stimulus and the recoloration requires high temperature. To solve these problems, we have designed and prepared CeO2-x nanodots as novel photocatalytic components in PCSSs that respond to two kinds of visible light. CeO2-x nanodots are prepared by a solvothermal reaction with l-ascorbic acid as the reducing agent. CeO2-x nanodots with a size of ∼2 nm have a high concentration of oxygen vacancies, which confers a broadened photoabsorption with an edge at 500 nm, as well as a weak photoabsorption tail in the visible region (500-800 nm). To realize the color switching, both the CeO2-x/Dye/H2O solution and CeO2-x/dye/hydroxyethyl cellulose (HEC)-coated fabrics have been prepared. Under blue (450 nm) light irradiation, both the solution and fabric show a rapid discoloration in 30 s and 150 s, respectively, due to the efficient photocatalytic reduction of the redox dye by CeO2-x. Conversely, red (630 nm) light irradiation with air confers a rapid recoloration in 35 s for the solution and 200 s for the fabric, resulting from CeO2-x-mediated self-catalyzed oxidation. In particular, the required images and letters can be remotely printed on CeO2-x/Dye/HEC-coated T-shirts with a 450 nm laser pen, and then erased with 630 nm light, with high reversibility and stability. Therefore, the present CeO2-x/Dye/HEC PCSSs have great potential to construct rewritable smart fabrics for various applications.
光可逆颜色切换系统（PCSSs）在各种应用中受到了越来越多的关注，但在大多数PCSSs中，变色过程通常依赖有害的紫外线作为刺激，而重新显色则需要高温。为了解决这些问题，我们设计并制备了CeO2-x纳米点，作为PCSSs中响应两种可见光的新型光催化组件。CeO2-x纳米点通过以L-抗坏血酸作为还原剂的溶剂热反应制备。尺寸约为2 nm的CeO2-x纳米点具有高浓度的氧空位，这赋予了其在500 nm处有边缘的宽化光吸收以及在可见光区域（500 - 800 nm）的弱光吸收尾。为了实现颜色切换，制备了CeO2-x/染料/H2O溶液和CeO2-x/染料/羟乙基纤维素（HEC）涂层织物。在蓝色（450 nm）光照射下，由于CeO2-x对氧化还原染料的高效光催化还原，溶液和织物分别在30 s和150 s内迅速变色。相反，在有空气的情况下用红色（630 nm）光照射，溶液在35 s内、织物在200 s内迅速重新显色，这是由CeO2-x介导的自催化氧化导致的。特别地，所需的图像和字母可以用450 nm激光笔远程打印在CeO2-x/染料/HEC涂层的T恤上，然后用630 nm光擦除，具有高可逆性和稳定性。因此，目前的CeO2-x/染料/HEC PCSSs在构建用于各种应用的可重写智能织物方面具有巨大潜力。
