Huangjie Lu,Zhaofa Zheng,Zi-Jian Li,Hongliang Bao,Xiaojing Guo,Xiaofeng Guo,Jian Lin,Yuan Qian,Jian-Qiang Wang
Rational design and synthesis of new photochromic sensors have been active research areas of inquiry, particularly on how to predict and tailor their properties and functionalities. Herein, two thulium 2,2′:6′,2′′-terpyridine-4′-carboxylate (TPC)-functionalized metal–organic hybrids, Tm(TPC)2(HCOO)(H2O) (TmTPC-1) and Tm(TPC)(HCOO)2 (TmTPC-2) with different photochromic response behaviors, have been successfully prepared, allowing for straightforward investigations of the structure–property correlation. Single-crystal X-ray diffraction and electron paramagnetic resonance analyses revealed that the incorporation of a unique dangling decorating TPC unit in TmTPC-1 offers a shorter and more accessible π–π interaction pathway between the adjacent TPC moieties than that in TmTPC-2. Such a structural feature leads to the production of radical species via a photoinduced intermolecular electron-transfer (IeMCT) process upon UV or X-ray irradiation, which ultimately endows TmTPC-1 with a rather unusual UV and X-ray dual photochromism. A linear relationship between the change of UV–vis absorbance intensity and X-ray dose was established, making TmTPC-1 a promising dosimeter for X-ray radiation with an extremely high energy threshold (30 kGy). To advance the development for real-world application, we have fabricated polyvinylidene fluoride (PVDF) membranes incorporating TmTPC-1 for functioning either as a UV imager or as an X-ray radiation indicator. Lastly, TmTPC-1 exhibits high thermal stability (up to 400 °C) and radioresistance (at least 900 kGy), and also excellent reversibility of photochromic transformation (at least 5 cycles).
Effective and suitable utilization of solar energy was achieved using a full-spectrum-response photocatalyst AgBr/Cs x WO 3 , applied in the photocatalytic and photochromic field. Benefitting from near-infrared (NIR) absorption ability of Cs x WO 3 , AgBr/Cs x WO 3 exhibits enhanced visible-near-infrared (Vis-NIR) driven photocatalytic activity. Based on X-ray photoelectron spectroscopy (XPS), photoluminescence spectra (PL), and the photoelectrochemical analysis, AgBr and Cs x WO 3 formed a Z-scheme system at the interface to efficiently separate and transfer photo-induced electrons at a fast rate. The quenching experiment and the electron spin resonance (ESR) tests indicated that the photocatalytic reaction is activated by the production of superoxide radicals. Furthermore, the photochromic analysis to different light exhibits the AgBr/Cs x WO 3 heterostructure is stable under visible light with negligible photodeposition of AgBr, and has excellent double photochromic activity with visible-shielding effect of AgBr to Ag 0 and infrared-blocking effect of Cs x WO 3 under ultraviolet light. This research provides new insights into the manufacture of energy-efficient and environmentally friendly materials that provide excellent performance in both thermal insulation and decontamination.