Synthesis and photoluminescence characterization of ZnO nanoparticles

Zinc oxide (ZnO) precursors were produced via a simple precipitation method from zinc nitrate (Zn(NO3)2) and ammonium carbonate ((NH4)2 CO3) in aqueous solutions. ZnO nanoparticles were synthesized by heating the precursor with different pH of reaction medium at different annealing temperatures. The precursors and synthesized ZnO nanoparticles were characterized by XRD, SEM and TG–DTA measurements. The effect of annealing temperature and pH impact on ZnO products with respect to the morphological and photoluminescence (PL) characteristics has been investigated. It is found that the synthesized ZnO nanoparticles have pure wurtzite structure and the average crystallite size increased with increasing annealing temperature. TG–DTA curves of the ZnO precursor indicate that no thermal effect and no further weight loss were observed above the annealing temperature at 450 °C. SEM micrographs reveal that the particle sizes increase with increasing the annealing temperature. Finally, the room temperature PL spectra confirm that irrespective to the pH of the reaction all PL spectra have only a strong UV emission peak, and with increasing the annealing temperature the visible deep level DL emission intensity increased. - Highlights: ► ZnO precursor was prepared by the precipitation method. ► The ZnO crystallite sizes were increased with increasing the annealing temperature. ► SEM analysis indicated some aggregation due to high surface energy in the products. ► TG–DTA indicates no thermal effect and no further weight loss observed above 450 °C. ► The room temperature PL spectra showed that irrespective of the pH, all products have only a strong UV emission.