Photoinduced reduction and heat-induced oxidation of silver in transparent RSiO(3/2) and RSiO(3/2)-TiO(2) films.
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.
Kawamura
Go
G
Department of Materials Science, Toyohashi University of Technology, Toyohashi 441-8580, Japan. gokawamura@tutms.tut.ac.jp
Sato
Shizuka
S
Kogure
Toshihiro
T
Daiko
Yusuke
Y
Muto
Hiroyuki
H
Sakai
Mototsugu
M
Matsuda
Atsunori
A