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

Abstract

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 (Ca-0.97)(3)(Y-0.92)(GaO)(3)(BO3)(4):0.01Ce(3+),-0.03Mn(2+),0.07Tb(3+) 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.