Luminescence properties and energy transfer in Ca3(PO4)2:Ce3+, Tb3+ phosphors

Abstract

A series of Ce3+, Tb3+ and Ce3+–Tb3+-doped Ca3(PO4)2 were prepared by high-temperature solid-state reaction, and X-ray diffraction was used to characterize the phase structure. The photoluminescence and energy transfer properties of Ce3+- and Tb3+-doped Ca3(PO4)2 host were investigated. Under the 290-nm radiation excitation, the emission spectrum of Ca3(PO4)2:Ce3+ shows one broad band that peaks at 360 nm, which is attributed to the 5d–4f transition of Ce3+. Ce3+ and Tb3+ co-doped Ca3(PO4)2 phosphors exhibit both blue emission from Ce3+ ions and intense green emission lines from Tb3+ at the excitation of Ce3+. These results indicate that there exits valid energy transfer from Ce3+ to Tb3+. The energy transfer from Ce3+ to Tb3+ in Ca3(PO4)2 was demonstrated to be a resonant type via electric dipole–quadrupole interaction. The critical distance of energy transfer was also calculated. Moreover, the emitting color of Ca3(PO4)2:Ce3+, Tb3+ can be tuned by appropriately adjusting the relative doping composition of Ce3+/Tb3+.