Size-controllable synthesis of spherical ZnO nanoparticles: Size- and concentration-dependent resonant light scattering

A new and simple direct precipitation method assisted with ultrasonic agitation was proposed for the preparation of spherical ZnO nanoparticles. The size of the ZnO nanoparticles, 10 nm to 85 nm, was tuned through controlling the calcination temperature and changing the ratio of the reactants. The resonant light scattering (RLS) of the ZnO nanoparticles dispersed/suspended in aqueous solution of Triton X-100 was studied under room temperature. It was found that the ZnO nanoparticles of different size or concentration all have a characteristic RLS peak at 387 nm. Under optimal conditions, the RLS intensity was proportional to the ZnO concentration in the range of 7.3 × 10^?8–1 × 10^?4 mol L^?1, while the cubic root of the RLS intensity was found to be proportional to the size of ZnO nanoparticles. Further, the quantitative relationship of the size of the ZnO nanoparticles versus the calcination temperature was derived, and this could be used to forecast/control the nano-size in the nano-ZnO preparation.