Morphological control of Y₂O₃:Eu phosphor particles by adding polymeric precursors in spray pyrolysis

The Y₂O₃:Eu phosphor particles having a spherical shape and dense morphology were prepared by a pilot-scale spray pyrolysis process which involved the introduction of polymeric precursors in the spray solution. The Y₂O₃:Eu particles prepared from the solution without polymeric precursors had a hollow and fractured structures. However, the particles prepared from the solutions with citric acid and ethylene glycol had a completely spherical shape and dense morphology. The polymeric chains formed from the esterification reaction between carboxyl and alcohol groups changed the drying and decomposition stages of the droplets. The ratio of citric acid, ethylene glycol and their concentrations were critical factors in the control of the morphology of the Y₂O₃:Eu phosphor particles. The mean crystallite sizes of the particles prepared from solutions with and without citric acid and ethylene glycol were 49 nm and 33 nm, respectively. The maximum photoluminescence intensity of the particles prepared from the solution with suitable concentrations of citric acid and ethylene glycol was 125% of that of the particles prepared from the solution without polymeric precursors.