Photoluminescence property adjustment of ZnO quantum dots synthesized via sol-gel method

摘要

AbstractQuantum dots (QDs) are zero dimensional nanomaterials and promising materials in the fluorescent label, LED display, metal ions sensor, catalysis and so on. ZnO QDs are one kind of ideal QDs, due to their non-poisonous, easy prepared, plentiful, economical properties. The visible light emission colour and quantum yields of ZnO QDs is determined by their band structures and defect structures. Main method to adjust the optical performance is controlling the particle sizes, band structures and defect structures by adjusting synthesis method and doping. Therefore, it is important to investigate the mechanisms of particle growth and defects variation. In this paper, a sol–gel method were employed to synthesize stable ZnO QDs used in fluorescence labeling and solar cells. Effects of reactants concentration, material ratio and reaction time on particle sizes and defects structures of ZnO QDs synthesized by sol–gel method were studied. Changing the synthesis process of ZnO QDs can adjust their photoluminescence defects structures and particle sizes. The ZnO QDs synthesized with c(Zn2+) = 0.1 mol L− 1, n(OH−):n(Zn2+) = 2:1, for 1.5 h reaction showed the highest photoluminescence quantum yields (40%) with green emission under 359 nm UV-light excitation. The visible light emission of the ZnO QDs synthesized with c(Zn2+) = 0.025 mol L− 1, n(OH−):n(Zn2+) = 3:1, for 1.5 h min is blue-green colour excited under 337 nm.