Xu Ding

White-Emitting Phosphor Ca2BO3Cl : Ce3 + , Eu2 + for UV Light-Emitting Diodes

Ce 3+ and Eu 2+ coactivated Ca 2 BO 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 Eu 2+ . The luminescent mechanism is explained by the resonance-type energy transfer from Ce 3+ to Eu 2+ , 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 Ce 3+ /Eu 2+ .

A Dual-Emission Phosphor LiCaBO3 : Ce3 + , Mn2 + with Energy Transfer for Near-UV LEDs

A series of Ce 3+ and Mn 2+ co-doped LiCaBO 3 single composition phosphors were synthesized by a solid-state reaction method, and their luminescent properties had also been investigated. Ce 3+ and Mn 2+ co-doped LiCaBO 3 phosphors showed a blue and orange dual emission under the near-UV light excitation within the wavelength range of 325-375 nm, resulting from the 5d-4f transitions of Ce 3+ and the d-d forbidden transition of Mn 2+ , respectively. The energy transfer from Ce 3+ to Mn 2+ was investigated and demonstrated to be a resonance-type via a dipole-dipole mechanism with the critical distance of about 4.1 A. The photoluminescence intensity ratio of blue and orange emission could be tuned by adjusting the concentration of Ce 3+ and Mn 2+ . The potential applications of these dual-emitting phosphors are the alternative blue and orange-emitting light emitting diode (LED) conversion phosphors due to their strong excitation bands in the wavelength range of 325-375 nm.