title: Random laser action of ZnO@mesoporous silicas.
abstract: ZnO@mesoporous silica nanocomposite was prepared by the impregnation method, and very efficient laser action was highlighted. As revealed by high-resolution transmission electron microscopy (HR-TEM), nanometric ZnO particles are confined inside the mesochannels of CMI-1 mesoporous silicas. Upon excitation at 3.6 eV of a femtosecond pulsed laser and at low pumping intensity, the ZnO@mesoporous silica showed a broad photoluminescence (PL) band corresponding to the excitonic recombination of ZnO. When the pumping intensity is increased up to a threshold (2.5 mJ cm(-2)), the excitonic emission turns to stimulated emission through a mechanism which will be discussed. The same threshold value was obtained with another excitation source and nanocomposites with different ZnO loadings inside the CMI-1 mesoporous silica. These results allow a better understanding of the random laser effect in ZnO@mesoporous silica and, consequently, a model has been proposed to explain this phenomenon. Based on these new observations, many new applications can be considered since short-wavelength devices are required by industry to design new information storage supports.
authors.affiliation: Laboratory of Inorganic Materials Chemistry, The University of Namur (FUNDP), 61 rue de Bruxelles, B-5000 Namur, Belgium.
authors.forename: Claire
authors.initials: C
authors.lastname: Bouvy
authors.forename: Evgeny
authors.initials: E
authors.lastname: Chelnokov
authors.forename: Rui
authors.initials: R
authors.lastname: Zhao
authors.forename: Wladimir
authors.initials: W
authors.lastname: Marine
authors.forename: Robert
authors.initials: R
authors.lastname: Sporken
authors.forename: Bao-Lian
authors.initials: BL
authors.lastname: Su