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 |
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| 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 |
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