Luminescence and Energy Transfer of Color-Tunable Y2Mg2Al2Si2O12:Eu2+,Ce3+ Phosphors

Abstract

Color-tunable phosphors can be obtained through codoping strategies and energy transfer regulation. Ce³⁺ and Eu²⁺ are the most common and effective activator ions used in phosphor materials. However, the energy transfer from Eu²⁺ to Ce³⁺ is rarely reported. In this work, Y₂Mg₂Al₂Si₂O₁₂(YMAS):Eu²⁺,Ce³⁺ phosphors were successfully synthesized, which was confirmed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Rietveld refinement, scanning electron microscopy (SEM) and element mapping images, and spectral information. The luminescent color of YMAS:Eu²⁺,Ce³⁺ phosphors could be tuned from blue to cyan to light green to yellow-green and finally to green-yellow, which was achieved by adjusting the energy transfer between different dopants. The energy transfer from Eu²⁺ to Ce³⁺ was confirmed by photoluminescence spectra and fluorescence decay curves. Within the experimental gradient, the energy transfer efficiency could reach up to 48%. At 373 K, the Y_1.99Mg_1.99Al₂Si₂O₁₂:0.01Eu²⁺,0.01Ce³⁺ (YMAS:0.01Eu²⁺,0.01Ce³⁺) phosphor exhibited a total integral emission loss of only 8%, and the emission peak intensity decreased to 95%, indicating the excellent thermal stability. The white light-emitting diode (WLED) fabricated by the YMAS:0.01Eu²⁺,0.01Ce³⁺ phosphor has the same level correlated color temperature (CCT = 5841 K), greatly improved color rendering index (R_a = 87.8), and higher quality white light color (CIE = (0.3258, 0.3214)) than the WLED made by the YMAS:0.01Eu²⁺ phosphor, indicating that the performance of the phosphor was significantly improved by introducing Ce³⁺. This work provides an effective guide for the design and development of highly efficient color-tunable phosphors involving energy transfer from Eu²⁺ to Ce³⁺ in some specific materials, such as garnet structures.