title: Preparation of novel silica-cadmium sulfide composite nanoparticles having adjustable void space by size-selective photoetching.
abstract: The size-selective photoetching technique was used to control the size of a CdS nanoparticle inside a silica shell. With monochromatic light irradiation, the diffuse reflectance spectra of silica-coated CdS nanoparticles were blue-shifted, and the size of the resulting CdS nanoparticles incorporated in the silica shells was adjustable by varying the wavelength of irradiated light. TEM observation revealed that the original CdS nanoparticle seemed to be in close contact with the amorphous silica shell to leave almost no clearance, while the monochromatic light irradiation caused the decrease in the size of CdS particles, resulting in the formation of a void space between the photoetched CdS core particle and the silica shell. The average void spaces available in the shells were calculated to be ca. 1.4 and 2.4 nm with the irradiation at 514 and 458 nm, respectively. These results indicated that the size-selective photoetching technique enables the regulation of void space formed in the core-shell structure by choosing the wavelength of irradiation light.
authors.affiliation: Catalysis Research Center, Graduate School of Environmental Earth Science and Center for Advanced Research of Energy Technology, Hokkaido University, Sapporo 060-0811, Japan.
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Torimoto
authors.forename: Jocelyn Paz
authors.initials: JP
authors.lastname: Reyes
authors.forename: Kentaro
authors.initials: K
authors.lastname: Iwasaki
authors.forename: Bonamali
authors.initials: B
authors.lastname: Pal
authors.forename: Tamaki
authors.initials: T
authors.lastname: Shibayama
authors.forename: Kenji
authors.initials: K
authors.lastname: Sugawara
authors.forename: Heishichiro
authors.initials: H
authors.lastname: Takahashi
authors.forename: Bunsho
authors.initials: B
authors.lastname: Ohtani