Appearance of New Absorption Bands due to the Heavy UV-Light Irradiation in CsBr:Au^-Crystals

Creation of CsAu nanoclusters by UV‐light irradiation on CsBr:Au– crystals

“…It is well known that the sharp zero-phonon lines and the phonon side bands having non-Gaussian shape are often observed in the spectra of the F aggregate centers in alkali halides: the R and N centers being made of three and four F centers, respectively [25]. From the analogy with the F aggregate centers, we attributed the sharp absorption lines around 2.14 eV in the irradiated CsBr:Au -crystals to the larger aggregate centers than the Au -dimer centers (probably aggregate centers made of three Au -centers) [15]. The assignment is consistent with the facts that the sharp absorption lines around 2.14 eV begin to appear slightly later after the growth of the dimer bands at 4.4 and 4.6 eV.…”

“…The crystallographical structure of this material is almost equal to that of the CsBr crystal. In a previous paper [15], we reported the appearance of new absorption bands in the CsBr:Au -crystals with the heavy UV light irradiation at room temperature (RT).…”

“…As the CsAu compound also decomposes rapidly in air, the compound is hard to handle. We have attempted to fabricate CsAu nanoclusters or microcrystals by means of the photoinduced aggregation phenomenon of the Au -ions doped in cesium halides [15]. The Au -ions doped in alkali halide crystals aggregate and form paired Au -ions (dimer), when the alkali halide crystals are irradiated with an ultraviolet (UV) light [16][17][18].…”