Synthesis and photoluminescence of Eu3+/Dy3+-doped CaGdAlO4 phosphors for white light emitting diodes

Abstract

ABSTRACTEu3+/Dy3+-doped CaGdAlO4 phosphors were prepared by a typical sol-gel method. X-ray diffraction patterns indicate that all CaGd1-x-yAlO4:xEu3+, yDy3+ phosphors have the standard structure of CaGdAlO4. CaGd1-yAlO4:yDy3+ phosphors exhibit both blue and yellow emissions under the excitation of 274 nm, and CaGd1-xAlO4:xEu3+ phosphors show a strong red emission under the excitation of near-UV light, while only Eu3+ emission is appeared in the photoluminescence spectra of Eu3+, Dy3+-codoped CaGdAlO4 phosphors. But the red emission intensity of CaGd1-x-yAlO4:xDy3+, yEu3+ increases obviously with Dy3+ introduced, and the luminescence intensity of CaGd0.98AlO4:0.01Eu3+, 0.01Dy3+ is 3.0-fold higher than that of CaGd0.99AlO4:0.01Eu3+ phosphor. The chromaticity coordinates for CaGd0.99AlO4:0.01Dy3+, CaGd0.99AlO4:0.01Eu3+ and CaGd0.98AlO4:0.01Eu3+, 0.01Dy3+ are (0.311, 0.365), (0.645, 0.354) and (0.644, 0.356), respectively. The values of lifetime of CaGd0.99AlO4:0.01Eu3+, CaGd0.98AlO4:0.01Eu3+, 0.01Dy3+, CaGd0.97AlO4:0.01Eu3+, 0.02Dy3+ and CaGd0.96AlO4:0.01Eu3+, 0.03Dy3+ phosphors are 1.619, 1.456, 1.207 and 1.385 ms, respectively.