Highly efficient and thermally stable luminescence of Ca3Gd2Si6O18:Ce3+,Tb3+ phosphors based on efficient energy transfer

Abstract

As phosphor-converted white light emitting diodes have emerged as new-generation light sources, developing phosphors with both high quantum efficiency (QE) and thermal stability is urgently required. One of the effective strategies is exploiting the nonradiative energy transfer to simultaneously improve the absorption of the activator and tune the emission of the sensitizer. In this work, we report a series of color-tunable phosphors by constructing an energy transfer system by co-doping Ce³⁺ and Tb³⁺ into Ca₃Gd₂Si₆O₁₈ (CGSO). We show that CGSO:Ce³⁺,Tb³⁺ not only exhibits color-tunable emission from violet (395 nm) to green (543 nm), but also possesses high internal QE (90.1%). Furthermore, we demonstrate that thermal stability can be significantly improved via efficient energy transfer from Ce³⁺ to Tb³⁺, which is mainly attributed to the fast energy transfer within the nearest Ce³⁺–Tb³⁺ pairs. Our results indicate that energy transfer from Ce³⁺ to Tb³⁺ provides a promising way to develop new green phosphors with high QE and superior thermal stability.