White-emitting phosphor Ca2BO3 Cl:Ce3+, Eu2+ for UV light-emitting diodes

Ce³⁺ and Eu²⁺ coactivated Ca₂BO ₃ Cl phosphors exhibit two blue and yellow emission bands under the excitation of UV light. An asymmetric blue emission originates from Ce ³⁺, whereas the yellow emission originates from Eu2+. The luminescent mechanism is explained by the resonance-type energy transfer from Ce ³⁺ to Eu²⁺, and the energy-transfer efficiency is also calculated by decline and growth of their emission relative intensities. In light of the principle of energy transfer, the varied emitted color of phosphor from blue through white and finally to yellow can be achieved by properly tuning the ratio of Ce³⁺ Eu²⁺.