Ca2BO3Cl:Ce3+,Eu2+: A potential tunable yellow–white–blue-emitting phosphors for white light-emitting diodes

Polycrystalline Ca2BO3Cl:Ce3+,Eu2+ phosphors were synthesized by a solid-state reaction and which could display tunable color emission from blue to yellow under an ultraviolet (UV) source by adjusting the ratio of Ce3+ and Eu2+ appropriately. The mechanism of resonance-type energy transfer from Ce3+ to Eu2+ was established to be electric dipole–dipole natured, and the critical distance was estimated to be 31 Å based on the spectral overlap and concentration quenching model. A white light was obtained from Ca2BO3Cl:0.06Ce3+,0.01Eu2+ phosphor with chromaticity coordinates (x=0.31, y=0.29) and relative color temperature of 7330 K upon excitation with 360 nm, which is potentially a good candidate as an UV-convertible phosphor for white light-emitting diodes (LEDs).