A Novel Single-Composition Trichromatic White-Light Ca3Y(GaO)3(BO3)4:Ce3+,Mn2+,Tb3+ Phosphor for UV-Light Emitting Diodes

A novel single-composition white-emitting phosphor Ca3Y(GaO)3(BO3)4:Ce3+,Mn2+,Tb3+ has been synthesized by a high-temperature solid-state reaction. The spectral overlap between the emission band of Ce3+ and the excitation band of Mn2+, which supports the occurrence of the energy transfer from Ce3+ to Mn2+, has been studied and demonstrated to be a resonant type via a dipole−quadrupole mechanism. Because there was no spectral overlap between the emission spectra of Ce3+ and excitation band of Tb3+ in our study, no energy transfer from Ce3+ to Tb3+ was observed, indicating that Ce3+ and Tb3+ were coexcited. Through effective resonance-type energy transfer and coexcitation, the chromaticity coordinates of Ca3Y(GaO)3(BO3)4:Ce3+,Mn2+,Tb3+ phosphors can be tuned from (0.152, 0.061) for Ca3Y(GaO)3(BO3)4:Ce3+ to (0.562, 0.408) for Ca3Y(GaO)3(BO3)4:Mn2+, and eventually reaching (0.314, 0.573) for Ca3Y(GaO)3(BO3)4:Tb3+. A white light-emitting diode (LED) was fabricated by using the white-emitting single-composition (Ca0.97)3(Y0.92)(GaO)3(BO3)4:0.01Ce3+,0.03Mn2+,0.07Tb3+ pumped by a 365 nm UV-chip. Our results indicated that the CIE chromaticity coordinates and correlated color temperature (CCT) for white UV-LEDs were (0.31, 0.33) and 6524 K, respectively. Therefore, our novel white Ca3Y(GaO)3(BO3)4:Ce3+,Mn2+,Tb3+ can serve as a key material for phosphor-converted white-light UV-LEDs.