The Synthesis And Luminescent Properties Of Rare Earth Doped Silicate Phosphors

Rare earth doped luminescent materials get more attention because they are the main light-emitting materials of human application and the materials of white LED. Silicate material is a good luminescent material matrix because of cheap raw materials, rich source,simple preparation method, stable thermal and chemical properties, and rare earth doped silicate luminescent materials have outstanding luminescent performance. Therefore, we choose strontium silicate as the matrix material with rare earth doped to improve the luminescent performance and application value.Rare earth doped strontium silicate luminescent material were synthesized by solid phase reaction method and sol-gel method and their luminescent properties were studied.First, we got the suitable temperature and time of the synthesis of the two processes. The luminescent properties and concentration quenching of Sm³⁺ doped Sr2SiO4 samples prepared by two methods were compared.Sr₂SiO₄:Re(Re=Eu²⁺、Eu³⁺、Dy³⁺) phosphors were prepared by solid phase reaction,and their luminous mechanism were discussed. It was found that Eu²⁺ doped samples can be excited by ultraviolet light（350 nm） to emit green light（500 nm）; Eu³⁺ doped samples can be excited by ultraviolet light（393 nm） to emit orange light（589 nm） and red light（614 nm）; Dy³⁺ doped samples can be excited by ultraviolet light（348 nm） to emit blue（478 nm） and yellow light（572 nm）, and can be used for making near ultraviolet/purple light excitation of white LED chip. Sr2SiO4:Re(Re=Sm³⁺、Ce³⁺、Sm³⁺/Ce³⁺) phosphors were prepared by solid phase reaction, and the up-conversion luminescence was detected in Ce³⁺doped samples. Ce³⁺ doped samples can be excited by ultraviolet、green and red light to emit blue light, when the excitation wavelength was 560 nm 、 706 nm, emitting light wavelength range was 370⁴80 nm. Sm³⁺ doped samples can be excited by ultraviolet light and blue light to emit red orange light. When Sm³⁺ and Ce³⁺ co-doped samples were stimulated under a 402 nm excitation wavelength, the luminescent intensity of Sm³⁺increased significantly, but of Ce³⁺ decreased. Because there was the energy transfer between Ce³⁺ and Sm³⁺, Ce³⁺ was the sensitizer and Sm³⁺ was the energy acceptor.