The Synthesis And Photoluminescence Properties Of Di-phase Calcium Phosphate Rgb Phosphors

Luminescence materials take Phosphate as hosts have been widely applied in various lighting and displaying instruments for their excellent thermal and chemical stability. Phosphate can be Classified by structural features :Halogen phosphates, rare-earth phosphate and other phosphate. Phosphate itself can't luminescence, so photoluminescence materials of phosphate can illuminate for the doped activator ions transiting. At present, the Fundamental research of photoluminescence materials of phosphate is the initial stage, and the main work focus on halogen phosphates and rare-earth phosphate. But the Luminescence Properties of these materials isn't satisfied, therefore which greatly restricts the applied scope. To solve this problem, the Re-doped diphase phase calcium phosphate (DCP) phosphors were synthesized by the precipitation method, and investigated their luminescence properties doped with different ions.The main content is as follows:1. We have synthesized DCP:Eu³⁺ ,DCP:Tb³⁺ and DCP:Eu²⁺ by a precipitation method. The phase and structure of the DCP phosphors were investigated by the X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The XRD and FTIR results indicated that DCP consisted of hydroxyaptite (HA) andβ-tricalcium phosphate (β-TCP) phases.2. The luminescence properties of DCP:Eu³⁺ ,DCP:Tb³⁺ and DCP:Eu²⁺ were investigated by the photoluminescence (PL) spectra. We discuss these materials'luminescence mechanism. The results indicate that:(1) The DCP: Eu³⁺ phosphors fluoresced under three visible light bands (396 nm, 463 nm and 535 nm), and the main emission peaks focus on 610nm-640nm. It is found that Eu³⁺ ions site Inversion symmetry center in the DCP crystal Compared ⁵D₀â†'⁷F₁ with ⁵D₀â†'⁷F₂. The ⁵D₀â†'⁷F₂ transitions of Eu³⁺ ions have three emission peaks under 463nm excitation. The most intense peak of 615nm was existed because the Ca²⁺ site is occupied by the Eu³⁺ ions in TCP. The other two peaks were associated with the ⁵D₀â†'⁷F₂ transition emission of Eu³⁺ ions in Ca (II) and Ca (I) sites of HA, respectively(2) The DCP: Tb³⁺ phosphors have four obvious emission peaks (488nm, 590nm and 619 nm) under 377nm. The most intense peaks at 540nm-560nm attribute ⁵D₄—⁷F₅ and include three emission peaks which were associated with the Tb³⁺ ions in Ca (II) and Ca (I) sites of HA and Ca site of TCP respectively.(3) There are two excitations which are at 300nm and 350nm in DCP: Eu²⁺. The emission spectra are different under different excitation peaks. There were two emission bands which were 415 and 470nm under 300nm, respectively. The emission peak at 470nm only exists under 350nm. The 5d level of Eu²⁺ ion can be affected round the Crystal field, or there exists defect center in the crystal, so the ions transition can relax which Lead to the redshift of emission peak.(4) When (Re(Re=Eu,Tb)+Ca)/P=1.3, the emission intensity of DCP: Re was the maximum.