Effect of surface area and crystallite size on luminescent intensity of Y₂O₃:Eu phosphor prepared by spray pyrolysis

The luminescent intensity of Y₂O₃:Eu phosphor prepared by spray pyrolysis was monitored as a function of the surface area and crystallite size. In order to control the surface area or the crystallite size, some organic additives and flux materials were introduced in the spray solution. The reduction of surface area, which was achieved by only controlling the quantity of the organic additive, was found to be helpful for the improvement of luminescent intensity of Y₂O₃:Eu particles. The addition of Li₂CO₃ flux to the spray solution with the organic additive of 0.3 M enlarged the surface area of Y₂O₃:Eu particles as a consequence of the reduction of particle size. Then, the increase of surface area did not lower the luminescent intensity of Y₂O ₃:Eu phosphor particles since the added Li₂CO₃ flux increased the crystallinity, simultaneously. It was found that the Y ₂O₃ particles with larger crystallite size had higher photoluminescence regardless of the surface area. Therefore, we concluded that the crystallinity is more important factor than the surface area and increasing the crystallite size is essentially needed to enhance the luminescent intensity of Y₂O₃ phosphor prepared by spray pyrolysis.