Sensitized anti-stokes luminescence centers in AgCl crystals

In the AgCl microcrystals with adsorbed methylene blue dye molecules, sensitized anti-Stokes luminescence centers formed as a result of a photostimulated low-temperature (77 K) process are observed. The emission is recorded on excitation of the samples by radiation with the flux density 1014−1015 photon cm−2 s−1 in the spectral range 620–750 nm corresponding to optical absorption in the adsorbed dye molecules and adsorbed Ag1, Ag2, and Ag3 clusters. It is shown that the anti-Stokes luminescence centers formed by photo-stimulation present (adsorbed dye molecule)—(silver subnanocluster) hybrid nanostructures, in which the bonding between the components is weak but sufficient to provide the possibility for two-photon interband transitions that occur due to transfer of the electron’s excitation energy from the dye molecule to the silver cluster with subsequent photoionization of the cluster.