Effect of the Elaboration Conditions on the Structural, Morphological and Luminescence Properties of ZnO Nanopowders

Pure ZnO nanopowders were synthesized by the sol-gel method, which has several advantages, among which we include, achieving low temperature deposition and synthesis of new hybrid organo-mineral materials. The effect of the elaboration conditions (the elaboration concentrations ratio of precursors (C-Z/C-A), the gelling temperature (T-g) and the gelling time (t(g)) on the structural, morphological and luminescence properties of ZnO nanopowders has been investigated. The chemical composition of the powders, determined by FTIR spectroscopy, indicate the exclusive presence of Zn-O bonds, as it is shown by the XRD spectra. The XRD results indicate also that the synthesized ZnO powder is a solid solution, crystallizing in pure wurtzite structure with a minimum grain size of about 23 nm for the powders prepared using: C-Z/C-A = 0.06%, T-g = 130 degrees C and T-g = 4 h. The morphological aspect, given by the SEM images, revealed that the powders are made of sheets, consisting of small particles agglomerated together. The photoluminescence study of the ZnO powders shows spectra with luminescence peaks from green to ultraviolet light, the more intensive emission is connected to the peaks of the blue luminescence.