LiCaBO3:Eu3+ phosphor was synthesized by high solid-state reaction method,and its luminescent characteristics were investigated. The emission and excitation spectra of LiCaBO3:Eu3+ phosphors exhibited that the phosphors could be effectively excited by near ultraviolet(400 nm) and blue(470 nm) light,and emitted red light. The effect of Eu3+ concentration on the emission spectrum of LiCaBO3:Eu3+ phosphor was studied. The results showed that the emission intensity increased with increasing Eu3+ concentration,and then decreased because of concentration quenching. It reached the maximum at 3mol.% Eu3+,and the concentration self-quenching mechanism was the d-d interaction according to the Dexter theory. Under the conditions of charge compensator Li+,Na+ or K+ incorporated in LiCaBO3,the emission intensities of LiCaBO3:Eu3+ phosphor were enhanced.
Ce3+/Eu2+ co-doped LiBaBO3 phosphor was synthesized by high temperature solid-state reaction method, and its luminescent character- istics were investigated. The hues of the LiBaBO3:Ce3+, Eu2+ phosphor varies from blue to white and eventually to yellow-green by properly tuning the Ce3+/Eu2+ ratio. Under UV excitation, white light was generated by coupling blue and yellow-green emission bands attributed to Ce3+ and Eu2+ emissions, respectively. The luminous efficacy of LiBaBO3:1%Ce3+, 2%Eu2+ calculated from the emission spectrum was about 290 lm/W.
A novel green phosphor,LiCaBO3:Tb3+,was synthesized by solid state reaction method,its luminescence characteristics were investigated,and the formation of phosphors were confirmed by X-ray powder diffraction(XRD).Its excitation band extended from 220 to 400 nm,which was coupled well with the emission of UV LED(350-410 nm).It exhibited a strong green emission located at 544 nm with chromatic coordination(0.25,0.58).The emission intensities of LiCaBO3:Tb3+ phosphor were influenced by varying Tb3+ concentration,moreover,could be enhanced by doping charge compensator Li+,Na+,and K+.
