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

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.