Efficient energy transfer and luminescence properties of Ca3Y(GaO)3(BO3)4:Tb3+,Eu3+ as a green-to-red colour tunable phosphor under near-UV excitation.

A series of Ca3Y(GaO)3(BO3)4:Tb3+,Eu3+ phosphors were prepared by a high-temperature solid-state reaction. Their phase structures were confirmed by powder X-ray diffraction and the element distribution was measured using transmission electron microscopy elemental mapping. The photoluminescence emission and excitation spectra and fluorescence lifetime were studied and discussed in detail. The results revealed that Eu3+ ions can be efficiently sensitized by Tb3+ ions under near-UV excitation. In addition, the energy transfer efficiency can be controlled by adjusting the ratio of Eu3+ and Tb3+ to realize colour tunable emission from green to red. For Ca3Y(GaO)3(BO3)4:0.50Tb3+,0.10Eu3+, the emission intensity at 425 K is 78.11% of that at 300 K, being available to near-UV LEDs.