Significant Enhancements in the Fluorescence and Phosphorescence of ZnO Quantum Dots/SiO2 Nanocomposites by Calcination

As light-emitting fillers for functional transparent polymer nanocomposites as encapsulating materials for solid-state lighting, nanoparticles should have a high emission intensity and a matching refractive index with polymer resin. In this work, ZnO quantum dots (QDs)/SiO2 (Z-S) nanocomposite particles with a prescribed Z-S ratio were facilely synthesized by hydrolyzing tetraethoxysilane in the ZnO QD containing ethanol solution. The fluorescence and phosphorescence of Z-S nanocomposite particles were investigated as a function of calcination temperature. The fluorescence emission intensity of the nanocomposite particles has been enhanced by 108% after calcination at 300 °C. The phosphorescence before calcination has a very low emission intensity of 0.34 au, while the phosphorescence has been significantly enhanced by 14.9 times after the calcination. Consequently, the calcined Z-S nanocomposite particles are promising as light-emitting fillers due to their intense fluorescence and phosphorescence and the matching refractive index with transparent epoxy matrix for functional transparent epoxy nanocomposites as encapsulating materials for solid-state lighting.