Multi-color Phosphor Material With Controllable Polycrystalline Phase Transformation And Crystallographic Sites

The development and application of low-cost and tunable phosphor for semiconductor lighting has been persued of the people.In this paper,rich crystal-types and cheap cement composition polycrystalline Ca₂SiO₄ are selected as phosphor host,based on the basic theories about crystal-phase transformation in Materials Science and sites engineering in crystallography,color-tuanble Ce³⁺/Eu²⁺ doped Ca₂SiO₄ phosphors were prepared by carefully controlling the polycrystalline phase transformation of Ca₂SiO₄ and the occupied sites of Ce³⁺/Eu²⁺ luminescence center.The phase change regulation mechanism of Ca₂SiO₄ polycrystalline was researched,the coordination polyhedron structure of luminescent centers in differenent and specific luminescent hosts with different substituted sites were investigated,the relationship between the luminescence properties and crystal structure of phosphor was illustrated deeper understanding the luminous character and luminous nature.The research results are shown as follows:1.Polycrystalline Ca₂SiO₄ is selected as the luminescent host,controlling meticulously the polycrystalline phase transformation of Ca₂SiO₄ by doping different crystal types of stabilizer ions,to prepare color-tunable Ce³⁺/Eu²⁺ doped five kinds of crystalline Ca₂SiO₄??-Ca₂SiO₄,?-Ca₂SiO₄,?'L-Ca₂SiO₄,?'H-Ca₂SiO₄,?-Ca₂SiO₄?phosphors by using crystallographic phase transformation engineering.The regulation mechanism of crystal type stabilizer ions on the Ca₂SiO₄ polycrystalline phase transformation was discussed and the luminescent properties of five kinds of crystal Ca₂SiO₄ phosphor were compared and studied.2.Choosing high temperature polymorphs of ?'L-Ca₂SiO₄,?'H-Ca₂SiO₄ and ?-Ca₂SiO₄ with multiple cation sites to prepare color-tunable Ce³⁺/Eu²⁺ doped ?'L-Ca₂ SiO,?'H-Ca₂SiO₄ and ?-Ca₂SiO₄ phosphor materials on account of crystallographic sites of engineering via regulating the occupied sites of activator which is achieved by changing the concentration of Ce³⁺/Eu²⁺.Through investigating the variation of the concentration of activator and site substitution situation of luminescence center in the host lattices,then combining with optical properties to illuminate reasons about the changes of luminescent properties which is closely related to the site substitution of activators.3.On the basis of the color-tunable Ce³⁺/Eu²⁺ doped Ca₂SiO₄ fluorescent material which is achieved by Ca₂SiO₄ polycrystalline phase change and sites occupied luminous center project,deep analysing the crystal structure of five forms of Ca₂SiO₄ and the crystal field splitting property,investigating the polyhedron structure of luminescence center in diverse and specific crystal forms of luminescent substrate from different substituted sites,clarifying the relevance between crystal structure and luminescent properties of phosphors.