Influence of dispersant on Y2O3: Eu3+ powders synthesized by combustion method

Y2O3: Eu3+ powders were synthesized by combustion method and the influence of dispersant was investigated. XRD analysis indicated that the particle size increased with a small amount of dispersant firstly and then decreased with a further increase of dispersant. The morphologies of the powders were studied by scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). SEM images revealed that an appropriate amount of dispersant could reduce the agglomeration significantly. Due to the increase of specific surface area, the charge transfer bands in the excitation spectra showed a red shift with the decrease of particle size. The emission spectra displayed that the reduction of agglomeration could enhance the luminescent intensity greatly. The decay curves of the powders were single exponential and the lifetime of 612 nm emission increased with the decrease of particle size. The two deexcitation processes were discussed, and the increase of lifetime with decreased particle size resulted from the combined effects of surface defects and effective refractive index.