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 angstrom based on the spectral overlap and concentration quenching model. A white light was obtained from Ca2BO3Cl:0.06Ce(3+),0.01Eu(2+) 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). (C) 2009 Elsevier B.V. All rights reserved.