Kinetics of ZnO nanoparticle formation via fluorescence measurements

The kinetics of ZnO nanoparticles was examined by fluorescence measurements. Emission peak intensities of the ZnO nanoparticles synthesized at different conditions were monitored during wet-chemical reactions. It was shown that the three stages of the reaction; nucleation, growth, and reaching the average size, can be followed by means of the fluorescence intensities corresponding to both band-edge (∼375 nm, ∼445 nm, and ∼485 nm) and deep-trap (∼520 nm and ∼545 nm) transitions. With both higher stirring velocity and temperature the particle formation is faster. Although the nucleation time is not affected by stirring velocity, higher temperature causes faster reaction rate in all stages including nucleation. This method can be used for controlling the size of the nanoparticles.