Fabrication And Research Of Borate Phosphor Used For White Leds

In this paper, several kinds of phosphor used for ultraviolet LED were fabricated by traditional high temperate solid stated method. The chief contents are given as follows:(1) LiBaB9O15:Eu3+ red phosphor was synthesized by high temperature solid state reaction. The emission spectrum shows a dominant peak at 618 nm and the excitation spectrum has two main peaks located at 400 nm and 470 nm. The intensity of LiBaB9O15: Eu3+ obviously improved with the increasing concentration of Eu3+, but the concentration quench was not happened. The role of charge compensation of K+ ions increased effectively the luminescent intensity of LiBaB9O15:Eu3+, and increased about 40%. So it can be used as the red compensating phosphor in "blue+yellow" model and the red phosphor in the system of tricolor phosphors by UV-LED based.(2) A novel green-emitting phosphor Ba3Tb(BO3)3:Ce3+ was prepared. The excitation spectrum contains a broad band extending from 360 to 400 nm, which matches the emission of UV-LED(350-410 nm). The effect of doped Ce3+ obviously improved the intensity of phosphor. The experimental results indicate that there exists an effective energy transfer from Ce3+ to Tb3+ in Ba3Tb(BO3)3 host. The best concentration of Ce3+ is 10%.(3) Base on the second experiment, the Ba3Tb(BO3)3:Eu3+phosphor was prepared. The excitation spectrum contains two main peaks located at 383 nm and 490 nm, which match the emission of UV and blue LED respectively. The best concentration of Eu3+ is 2%.(4) The luminescent properties of the single white emitting phosphor Dy3+ activated SrAl2B2O7 were studied. The effects of doped-Dy3+ concentration and charge compensations of Li+, Na+ and K+ on the emission intensity are also investigated. According to the Dexter's theory, we have demonstrated that the concentration self-quenching mechanisms are the d-d interaction.