Study on electrochromic-fluorescence switching performance of film based on silicomolybdotungstate and silica nanoparticles doped with negative charged dye

Abstract We developed a novel way to construct the multifunctional composite films with luminescence and redox properties in this study. Firstly, the luminescent molecule HOPTS (8-hydroxypyene-1,3,6-trisulfonic acid trisodium salt) was incorporated into the silica spheres to form the green emission silica materials, HOPTS@SiO2, that were characterized by SEM (scanning electron microscope), FTIR (fourier transform infrared spectroscopy) and luminescence spectroscopy to verify their structure, morphology and property. And then the luminescent silica materials were functionalized by APTES (3-aminopropyltriethoxysilane) to form the positively charged surface, HOPTS@SiO2-APTES+. Afterwards, the composite luminescent films containing HOPTS@SiO2-APTES+ and SiMoW (SiMoW10O398−) were constructed by the layer-by-layer (LBL) assembly method immediately. The films were characterized by fluorescence spectroscopy, UV-vis spectroscopy, CV (cyclic voltammetry), XPS (X-ray photoelectron spectroscopy) and AFM (atomic force microscopy) to confirm their composition, morphology and property. Finaly, the reversible electrochemical photoluminescent switch performance of the composite luminescent films was investigated by in situ spectroelectrochemical system. The results indicated that thus-prepared composite films, [(PEI/SiMoW)5/(HOPTS@SiO2-APTES+/SiMoW)25/(PEI/SiMoW)20], displayed stable luminescence switching performance and wide voltage range as well as favourable stability and reversibility.