Photoluminescence characteristics of the nano-sized red phosphor (Y _x,Gd_y)O₃:Eu³⁺_1-x-y by using liquid phase precursor methods

Y_x,Gd_y)O₃:Eu³⁺_1-x-y red phosphor was prepared at firing temperatures from 700 °C to 1400 °C by using liquid phase precursor methods. The particle sizes of the samples prepared at firing temperatures of 800 °C and 1000 °C were about 23 nm and 64 nm, respectively. The strongest absorption band of the samples excited at 613 nm was observed at 260 nm, which resulted from transitions toward the charge transfer state (CTS) corresponding to the 'Eu³⁺-O ^2-' interactions. At intense emission peak was observed at 613 nm due to the electric dipole transition of '⁵D_0- ⁷F₂' induced by the lack of inversion symmetry at the Eu³⁺ sites. We observed that the maximum emission intensity of the samples was about 82.3 % at 1400 °C.