Photoluminescence emission at aging in ambient air of ZnO:Ag nanocrystals obtained by ultrasonic spray pyrolysis

Scanning electronic microscopy (SEM), X ray diffraction (XRD) and photoluminescence (PL) methods have been applied to the study the structural and optical properties of ZnO:Ag nanorods prepared by the ultrasonic spray pyrolysis (USP) method. The temperature and time variation at the growth of ZnO:Ag films permits modifying the ZnO phase from the amorphous to crystalline, to change the size of ZnO:Ag nanorods as well as to vary their photoluminescence spectra. With increasing the process duration to 10 min the ZnO re-crystallization and additional oxidation take place at the growth temperature, which is more effective at 450 °C than at 400°C. XRD show that crystal phase appeared is wurzite with the parameters of hexagonal crystal lattice equal to a = 3.2498 Å and c = 5.2066 Å. The size of ZnO nanocrystalls was estimated on the base of SEM results. This size was equal to 50 - 150 nm in the dependence on crystallization duration. PL spectra of ZnO:Ag nanorods are complex and can be represented as a superposition of elementary PL bands with the peaks in the spectral ranges: 2.90 - 3.25 eV (I), 2.10 - 2.80 eV (II) and 1.45 - 1.61 eV (III).