Study On Luminescent Phosphors Of Rare Earth Co-doped Ba₂ALa?PO₄?₃?A=Sr,Ca?

The Phosphate phosphor has a long history, which made good effect in the application of rare earth tricolor lamps. The Phosphate phosphor has convenient synthesis, cheap and versatile advantages compared with other luminescent materials.The White light-emitting diodes?w-LEDs? called the fourth generation light source, because of its energy efficiency, long life, environmental protection and other advantages, and the Strong applicabilit. The current academic for white light-emitting diodes is pursuing single-component white-light phosphors.In this paper, several phosphate phosphor was made by the high-temperature solid-state reaction. Studying with the energy transfer in Tm³⁺-Dy³⁺ and Tb³⁺-Eu³⁺, the photoluminescence properties of the phosphors was researched. On the basis of the single-coped with Dy³⁺, the Tm³⁺ and Dy³⁺ were doped to make phosphor. The study found that the phosphor can be prepared as a white LED phosphor when excited by UV or near-UV's.First,the Dy³⁺ was Doped into Ba₂ALa?PO₄?₃ by the high-temperature solid-state reaction. Excited by 350 nm the emission and excitation spectrum was measured. The best doping concentration is 0.08, The quenching mechanism is proved to be electric dipole- dipole interaction.Secondly, the Ba₂SrLa_1-x-y?PO₄?₃:xTm³⁺-yDy³⁺ phosphors were synthesized by conventional solid-state reaction method. It was found that the energy transfer from Tm³⁺ to Dy³⁺ was demonstrated by analyzing the photoluminescence and photoluminescence excitation spectra of Ba₂SrLa_1-x-y?PO₄?₃:x Tm³⁺-yDy³⁺. The light color that this phosphors emit under the excitation of UV light could be changed from blue to white and then to yellow by using the energy transfer from Tm³⁺ to Dy³⁺. The light color was very close to?x=0.33, y=0.33? which is the white color chromaticity coordinatesThirdly, the Ba₂SrLa1-x-y?PO₄?₃:xTb³⁺-yEu³⁺ phosphors were synthesized by conventional solid-state reaction method. It was found that the energy transfer from Tb³⁺ to Eu³⁺ was demonstrated by analyzing the luminescence spectra and the decay times of Ba₂SrLa_1-x-y?PO₄?₃:xTm³⁺-yDy³⁺. The color of phosphors under the excitation of UV light could be changed from green to yellow and then to red by using the energy transfer from Tb³⁺ to Eu³⁺.Finally, the Ba₂ Ca La_1-x-y-z?PO₄?₃:xTm³⁺-yDy³⁺-zEu³⁺ were made by the solid-state reaction method. The Ba₂CaLa?PO₄?₃ was doped with Dy³⁺, Tm³⁺ and Eu³⁺ ions. The energy transfer from Tm³⁺to Dy³⁺ ions was discovered by analyzing the luminescent spectra and the decay times when co-doped with Dy³⁺ and Tm³⁺. With the Dy³⁺, Tm³⁺, Eu³⁺ co-activated in Ba₂ Ca La?PO₄?₃ phosphors, the emission color can be changed from blue to white and then to red. It was very close to ideal white light?0.33, 0.33?. Meanwhile, the CIE chromaticity diagrams of the phosphors was also be in the range of warm white light under 394 nm excitation.