Abstract:

The blue white LiSrBO₃∶Ce³⁺ phosphor was synthesized with solid-state method. The emission spectrum of LiSrBO₃∶Ce³⁺ phosphor shows one dissymmetrical band at 436 nm. The excitation spectrum for 436 nm emission has broad band at 369 nm. The crystallographic sites of Ce³⁺ in LiSrBO₃ were calculated by Van Uitert formula. The results show that the emission band centered at 433 nm originates from the Ce³⁺ center of the nine compounds, the other emission band centered at 469 nm originates from the Ce³⁺ center of the eight compounds. The effect of Ce³⁺ molar fraction on luminescent intensity of LiSrBO₃∶Ce³⁺ phosphor was investigated, the result shows that the luminescent intensity firstly increases with increasing Ce³⁺ molar fraction, then decreases, and reaches the maximal value at 3% Ce³⁺. The concentration quenching mechanisms are the D-D interaction by Dexter theory. Under the condition of doping charge compensation Li⁺, Na⁺ and K⁺, the emission spectrum intensity of LiSrBO₃∶Ce³⁺ was heightened. The relative emission spectrum of the blue white-emitting InGaN-based LiSrBO₃∶Ce³⁺ LED was investigated, and the CIE chromaticity of InGaN-based LiSrBO₃∶Ce³⁺ LED is (x=0.289, y=0.293).

Key words: White LED; LiSrBO₃∶Ce³⁺; Crystallographic site; Luminescent characteristic