Highly efficient and thermal stable La2Si2O7:Ce3+,Tb3+,Eu3+ phosphors: Emission color tuning through terbium bridge.

Abstract A series of emission color tunable Ce3+, Tb3+, and Eu3+ co-doped La 2 Si 2 O 7 (LSO) phosphors have been prepared via a solid state reaction. The crystal structure, luminescence properties, and thermal stability of the phosphors were studied in this paper. There exists two kinds of energy transfer (ET) modes under UV excitation, namely, electric dipole-dipole interaction for Ce3+→Tb3+ and terbium bridge model [Ce3+→(Tb3+) n →Eu3+] for LSO:Ce3+,Tb3+,Eu3+ system. The emitting color of the phosphors can be tuned from green to yellow and eventually to orange-red through the Ce3+→Tb3+→Eu3+ energy transfer. Although codoping Tb3+ and Eu3+ into La 2 Si 2 O 7 :Ce3+ leads to the reduction of thermal stability, it still remains 80% for LSO:0.05Ce3+,0.8 Tb3+,0.02Eu3+ at 150 °C when compared to that at room temperature. The absolute quantum yield (QY) increases from 71.04% (LSO:0.05Ce3+) to 95.60% (LSO:0.05Ce3+, 0.6 Tb3+), while those of LSO:0.05Ce3+, y Tb3+,0.02Eu3+ samples remain more than 70%. These results indicate that the phosphors can be candidates for application in phosphor-converted white light-emitting diodes (pc-WLEDs). Graphical abstract Image 1 Highlights • La 2 Si 2 O 7 :Ce3+,Tb3+,Eu3+ has been prepared by a high-temperature solid state reaction. • The emitting color can be tuned from green to yellow and then to orange-red. • [Ce3+→(Tb3+) n →Eu3+] bridge is responsible for the enhancement of Eu3+ emission. • The quantum efficiency of 0.05Ce3+, y Tb3+,0.02Eu3+ codoped samples is more than 70%. • The phosphors exhibit good thermal stability. [ABSTRACT FROM AUTHOR]