Tunable emission, thermal stability and energy-transfer properties of SrAl2Si2O8: Ce3+/Tb3+ phosphors for w-LEDs

Ce3+/Tb3+ ions singly and co-doped SrAl2Si2O8 phosphors were synthesized by solid-state reaction method. The crystal structure, photoluminescence excitation and emission spectra, decay lifetime, energy transfer, quantum yield and thermal stability have been investigated in detail. The SrAl2Si2O8:0.04Ce3+ and SrAl2Si2O8:0.04 Tb3+ phosphors can emit blue and green light, respectively. Under 365 nm excitation, the emission color of SrAl2Si2O8:Ce3+, Tb3+ can be adjusted from blue to green by changing the proportion of Ce3+ and Tb3+ ions based on the energy transfer. With constantly increasing of Tb3+ ions concentration, the energy transfer efficiency from Ce3+ to Tb3+ in SrAl2Si2O8 host increased gradually and reached as high as 82.91%, the quantum yield was about 67.37%. The energy transfer mechanism is proved to be dipole-quadrupole interaction. Over 100 °C, 90% initial emission intensity can be still remained. The above results indicate that SrAl2Si2O8:Ce3+, Tb3+ is a potential multicolor emission phosphor for the application in w-LEDs.