Study On Luminescence And Stability Of Mn(Ⅳ)Doped Low Symmetry Composite Fluoride Red Light Material

The Mn⁴⁺doped red fluoride phosphor has excellent optical properties,it has a broad absorption in the blue region at 467 nm,which matches the blue wavelength of the Ga N chip,and Mn4+ions have a sharp red light emission peak at about 630 nm in the red region,which can improve the color rendering performance of white light LEDs and obtain high display Warm white light with color index.However,for the use of Mn⁴⁺doped fluoride phosphors synthesized at room temperature,most of the matrix crystal structure has relatively high symmetry,and there are relatively few studies on composite fluorides with low symmetry.Using the co-precipitation method to selectively prepare several low-symmetric composite fluorides to effectively dope Mn⁴⁺,explore its luminescence performance,and provide a feasible strategy for improving the water stability of Mn⁴⁺doped fluoride containing phosphors in the later stage.Firstly,this article is the synthesis of red phosphor based on Mn⁴⁺doped Cs Na Ge_0.5Ti_0.5F₆（CNGTF）at room temperature.By using K₂Mn F₆,Na F,Cs₂CO₃,Ge O₂ and Ti O₂ as raw materials,after a few hours of reaction in HF acid,Cs Na Ge_0.5Ti_0.5F₆:Mn⁴⁺（CNGTF:Mn）red phosphor can be obtained.We systematically explored the formation mechanism of the red phosphor CNGTF:Mn.In addition,the optical properties of CNGTF:Mn are systematically studied,and a detailed comparison is made with the red phosphors Na Cs Ti F₆:Mn⁴⁺（NCTF:Mn）and Cs Na Ge F₆:Mn⁴⁺（CNGF:Mn）.The study found that compared with the matrix with high crystal symmetry,CNGTF:Mn with low symmetry has better fluorescence performance,its fluorescence spectrum is more complicated and there is obvious red shift phenomenon.Secondly,this article has designed a new type of Mn⁴⁺doped Na Rb Sn F₆（NRSF）as the main lattice of the red phosphor,using a simple and efficient method at room temperature.Regarding the new red fluoride phosphor Na Rb Sn F₆:Mn⁴⁺（NRSF:Mn）,we conducted detailed research based on different organic solvents,such as acetone,methanol,ethanol and ethylene glycol.The results show that organic solvents can control the morphology,yield and luminescence properties of NRSF:Mn.By optimizing the synthesis conditions used in the reaction system,the luminous intensity of NRSF:Mn can be improved,which is of great significance for the practical application of WLED.Finally,this article studies a new type of Mn⁴⁺doped double-composite fluoride red light material Cs Na Ge_0.5Sn_0.5F₆:Mn⁴⁺,and by controlling the ratio of the central ion Ge⁴⁺to Sn⁴⁺,the matrix CNGSF unit cell can be adjusted arbitrarily The crystal field environment,and then by analyzing the emission spectrum of Cs Na Ge_xSn_1-xF₆:Mn⁴⁺（CNGSFM）under different ratios of the central ion,it is found that the red shift and blue shift of the emission spectrum can be achieved,and it is found that the low symmetry caused by crystal distortion is more conducive to enhancement The luminous intensity of the red phosphor Cs Na Ge_xSn_1-xF₆:Mn⁴⁺.However,due to the ultra-low symmetry of the structure and the characteristics of Mn⁴⁺doped fluoride phosphors,the luminescence of CNGSFM is quenched in humid environments.Therefore,the surface repair strategy we proposed using modifiers has greatly improved the material Compared with the conventional phosphor CNGSFM,the product after the modifier repair is soaked in water for 16hours,and it still maintains a stable luminous brightness.This work not only studied the relationship between the structure of Mn⁴⁺ion-doped fluoride-containing oxide phosphor and the luminescence performance,but also provided a feasible strategy for improving water stability.