Effects of temperature, stirring velocity and reactant concentration on the size and the optical properties of ZnO nanoparticles

► Possible band-edge and deep-trap transitions were observed. ► Emission spectrum peaks from the band edge do not show any shift upon changing the excitation wavelength. ► The emission peaks from the deep traps show some considerable shifts upon changing the excitation wavelength. ► Increasing temperature and stirring velocity result in increasing the size of the nanoparticles.