Fluorescence intensity and color purity improvement in nanosized YBO3:Eu

In order to improve the color purity of ${\mathrm{YBO}}_3:\mathrm{Eu},$ which is practically used as a plasma phosphor, the lowering of the structural symmetry is proposed and subsequently realized in nanosized ${\mathrm{YBO}}_3:\mathrm{Eu}$ so as to increase the contribution of ${}^5{D}_0{–}^7{F}_2$ transition of the luminescent centers, ${\mathrm{Eu}}^{\text{3+}}$ ions. Spherical ${\mathrm{YBO}}_3:\mathrm{Eu}$ nanocrystals were fabricated via thermal decomposition of complex precursors and could be crystallized at lower temperature than required by the bulks. The particle size could be controlled by adjusting the annealing temperature and time. Unlike the bulk ${\mathrm{YBO}}_3:\mathrm{Eu}$ synthesized by solid-state reaction, the quenching concentration increased with the decrease of the particle size. Furthermore, the fluorescence intensity and color purity were significantly improved in nanocrystals. Possible mechanisms responsible for these improvements were proposed.