Anti-stokes luminescence of Zn0.6Cd0.4S solid solutions with adsorbed organic dye molecules and few-atom silver clusters

Autor: A. N. Utekhin, Oleg V. Ovchinnikov, A. N. Latyshev, E. A. Kosyakova, A. B. Evlev, V. G. Klyuev, M. S. Smirnov
Rok vydání: 2007
Předmět:
Zdroj: Journal of Applied Spectroscopy. 74:681-686
ISSN: 1573-8647
0021-9037
DOI: 10.1007/s10812-007-0109-5
Popis: For microcrystals of Zn0.6Cd0.4S with adsorbed molecules of a number of organic dyes, we have observed sensitized anti-Stokes luminescence excited by radiation with wavelengths in the range 610–750 nm and flux density 1014–1015 photons/cm2·sec. The positions of the bands in the excitation spectra for such luminescence match those of the absorption spectra for the adsorbed dye molecules, which is evidence in favor of a cooperative mechanism for its appearance. We have shown that enhancement of the anti-Stokes luminescence is possible when silver atoms and few-atom clusters appear on the Zn0.6Cd0.4S surface in addition to the dye molecules. We hypothesize that its excitation in the latter case occurs as a result of two-photon optical transitions. These transitions occur sequentially, with transfer of an electron or the electronic excitation energy from the dye molecules to silver atoms and few-atom clusters adsorbed on the surface of Zn0.6Cd0.4S, creating deep localized states in the bandgap with photoionization energies 1.80–2.00 eV.
Databáze: OpenAIRE