Preparation And Properties Of Novel Phosphors For Full-spectrum LED Regulated By Topological Chemical Reaction

High-quality lighting is the development trend of future lighting.The original pure pursuit of brightness and power of LED light source has been transformed into high-quality and healthy lighting with light efficiency,color rendering performance,color temperature and other composite light color performance.As the core of LED,fluorescent conversion materials have become the focus of research.In addition,traditional methods are difficult to control the crystal field environment and local structure of the luminescence center.As a flexible and efficient means of local structure regulation,topological chemical reaction can achieve the regulation of the valence state and coordination structure of the target cations by extracting the coordination oxygen of the cations at low temperatures.In order to solve the problem of low luminous intensity and luminous efficiency of phosphors,topological chemical reaction strategy was introduced in this paper to optimize the performance of phosphors.The research contents are as follows:（1）High efficiency red phosphors were prepared by topological chemical reaction after synthesis,and the quantum yield（PLQY）of Sr₃WO₆:Mn⁴⁺phosphors increased from 3.1%to58.9%.The detailed structural and spectral analysis shows that the samples treated with high intensity luminescence have a larger W-O distance,and the volume of[（W/Mn）O₆]octahedron is larger than that of the precursors due to the formation of oxygen vacancy.We found that topological chemical reduction converts W⁶⁺ions to W⁵⁺without affecting the oxidation state of Mn⁴⁺ions.These changes lead to the release of chemical pressure around Mn⁴⁺ions,which significantly inhibits the non-radiative transition and thus greatly enhances the luminescence.（2）High-efficiency single-phase full-spectrum Ca₁₀K（PO₄）₇:Eu²⁺phosphors were synthesized by topological chemical reaction.The structure and luminescence properties of Ca₁₀K（PO₄）₇:Eu²⁺phosphors were studied by XRD,PLE/PL,XPS,EPR and other characterization methods.It was confirmed that oxygen vacancy was generated after topological chemical reaction,which regulated the Eu²⁺ionic crystal field.Achieve full spectrum high efficiency emission.The Ca₁₀K（PO₄）₇:0.02Eu²⁺phosphor was reduced by Al at1000℃for 2 h to obtain the white phosphor excited by UV,and finally the Ca₁₀K（PO₄）₇:0.02Eu²⁺phosphor was encapsulated into the white LED with the color display index up to 92.