title: Size Control of Silver-Core/Silica-Shell Nanoparticles Fabricated by Laser-Ablation-Assisted Chemical Reduction.
abstract: Aqueous colloidal silver nanoparticles have substantial potential in biological application as markers and antibacterial agents and in surface-enhanced Raman spectroscopy applications. A simple method of fabrication and encapsulation into an inert shell is of great importance today to make their use ubiquitous. Here we show that colloids of silver-core/silica-shell nanoparticles can be easily fabricated by a laser-ablation-assisted chemical reduction method and their sizes can be tuned in the range of 2.5 to 6.3 nm by simply choosing a proper water-ethanol proportion. The produced silver nanoparticles possess a porous amorphous silica shell that increases the inertness and stability of colloids, which decreases their toxicity compared with those without silica. The presence of a thin 2 to 3 nm silica shell was proved by EDX mapping. The small sizes of nanoparticles achieved by this method were analyzed using optical techniques, and they show typical photoluminescence in the UV-vis range that shifts toward higher energies with decreasing size.
authors.affiliation: Universidade Estadual de Campinas, IFGW , Campinas, São Paulo 13083-859, Brazil.
authors.forename: Victor A
authors.identifier: 0000-0003-1125-4447
authors.initials: VA
authors.lastname: Ermakov
authors.affiliation: Universidade Federal de Pernambuco, DQF , Recife, Pernambuco 50670-901, Brazil.
authors.forename: Ernesto
authors.initials: E
authors.lastname: Jimenez-Villar
authors.affiliation: Universidade Estadual de Campinas, IFGW , Campinas, São Paulo 13083-859, Brazil.
authors.forename: José Maria Clemente da
authors.initials: JM
authors.lastname: Silva Filho
authors.affiliation: Universidade Estadual de Campinas, IQ , Campinas, São Paulo 13083-859, Brazil.
authors.forename: Emre
authors.initials: E
authors.lastname: Yassitepe
authors.affiliation: LNNano, CNPEM , Campinas, São Paulo 13083-970, Brazil.
authors.forename: Naga Vishnu Vardhan
authors.initials: NV
authors.lastname: Mogili
authors.affiliation: Universidade Estadual de Campinas, IFGW , Campinas, São Paulo 13083-859, Brazil.
authors.forename: Fernando
authors.initials: F
authors.lastname: Iikawa
authors.affiliation: Universidade Federal de Pernambuco, DQF , Recife, Pernambuco 50670-901, Brazil.
authors.forename: Gilberto Fernandes
authors.initials: GF
authors.lastname: de Sá
authors.affiliation: Universidade Estadual de Campinas, IFGW , Campinas, São Paulo 13083-859, Brazil.|Universidade Federal do Ceará, DF , Fortaleza, Ceará 60440-900, Brazil.
authors.forename: Carlos Lenz
authors.initials: CL
authors.lastname: Cesar
authors.affiliation: Universidade Estadual de Campinas, IFGW , Campinas, São Paulo 13083-859, Brazil.
authors.forename: Francisco Chagas
authors.initials: FC
authors.lastname: Marques