Photoinduced reduction and heat-induced oxidation of silver in transparent RSiO3/2 and RSiO3/2–TiO2 films

Abstract

Photoinduced reduction, resulting in nanoparticle formation, and heat-induced oxidation of doped silver have been demonstrated in silsesquioxane (RSiO(3/2)) and RSiO(3/2)-TiO(2) films (R = methyl, vinyl, and glycidoxypropyl) synthesized via the sol-gel method. The occurrence of redox behavior in the doped silver, i.e. formation and dissociation of silver nanoparticles (AgNPs) in the films, was confirmed by UV-Vis spectroscopy, IR spectroscopy, X-ray diffraction and transmission electron microscopy. The films containing vinyl and glycidoxypropyl organic functional groups were found to effectively reduce silver ions upon UV irradiation, whereas the film containing the methyl group substituent did not. Incorporation of a TiO(2) component into the RSiO(3/2) films caused thermal dissociation of the AgNPs. The formation and dissociation of AgNPs in the films was reversible by reiterating the cycle of UV irradiation and heat treatment.

Ag-doped inorganic–organic hybrid films for rewritable hologram memory application

“…For instance, Ag-doped vinyl-silsesquioxane (ViSiO 3/2 )-TiO 2 films were synthesized by the following procedure [18]. ViSi(OC 2 H 5 ) 3 (Vi: vinyl group) in ethanol was partially hydrolyzed by mixing with AgNO 3 and HNO 3 .…”

“…UV-Vis and b IR spectra of Ag-doped ViSiO 3/2 -TiO 2 films before and after UV radiation for 10 min (230-440 nm, 50 mW cm -2 at 365 nm); c shows changes in absorbance at 420 nm of the film experienced repeated UV radiation for 10 min and heat treatment in air at 100°C for 1 h. Reproduced with permission from[18]. Copyright 2010 The Royal Society of Chemistry…”

“…The lattice fringe of 0.2 nm matches with Ag (200) planes. Reproduced with permission from[18]. For the purpose of better readability, this figure is slightly modified without losing its original information.…”

Sol-gel synthesis of novel photosensitive material with advanced holographic properties

“…The Ag + ion-doped films, in fact, showed sufficient homogeneity, reversibility, and durability for the practical use as holographic materials. 7) Sensitivity to visible light was further given to the films by bromination of Ag + ions, whereas the homogeneity and reversibility were deteriorated. 8) In this work, we found that the change of the halogen element from Br to Cl was very effective to improve reactivity upon visible light irradiation.…”

Titania-based functional nanocomposite materials fabricated by liquid processes

“…89) Application of micropatterning technique to hologram formation has also been reported. 90)95) The basic concept is to fabricate sub-micropatterns in recording media, which contain TiO 2 . Reversible hologram formation was demonstrated in AgCl nanoparticle-doped RSiO 3/2 TiO 2 films (R: glycidoxypropyl organic functional group) by visible light irradiation and heat treatment (Fig.…”