Absorption and photoluminescence properties of silver clusters in SiO2 matrix
Absorption and luminescence properties of silver nanoclusters embedded in SiO2 matrixes were studied experimentally. Thin SiO2 films with different amount of silver were produced by co-deposition of Ag and SiO2 onto the silica substrates in vacuum. The thus obtained films possess three peaks in absorption spectra at 297, 329 and 401 nm and two peaks in luminescence spectra at about 500 and 650 nm. We ascribed these spectral features to silver nanoclusters of different sizes that present in the film. Thermal annealing transforms both absorption and emission spectra of the films. Lager clusters that are formed after annealing possess one absorption band at 350–450 nm and one luminescence band at 510 nm. The luminescence was observed only in samples with the silver content of less than 2.2%. Quenching of the luminescence in samples with higher concentration of silver is due to the presence of larger particles with plasmonic properties.
KeywordsSilver cluster Thin film Dielectric matrix Absorption Luminescence
The reported study was funded by RFBR, according to the research Project No. 16-32-60028 mol_a_dk, by Ministry of Education and Science (Project 2014/190) and by the Government of Russia (Grant 074-U01).