Study On Sc-based Oxyfluoride Glass Ceramic

Rare earth/transition metal ion-doped oxyfluoride glass ceramics,as a kind of optical functional bulk composite materials,have excellent mechanical properties and luminescence performance through precipitation of specific nanocrystalline particles in the glass matrix,so they have potential application prospects in optical communication,solid-state lasers and three-dimensional display.For the luminescence of glass ceramics,the structure control of nanocrystalline matrix and the distribution of luminescence center are the key factors on the luminescence efficiency.Therefore,it is very important to find new matrix materials with excellent properties.Scandium(Sc),as a rare earth element with the smallest ionic radius,is founded in the very top of IIIB and the beginning of transition element in the periodic table,which make the optical properties of Sc-based fluoride material are different from other rare earth fluoride materials.Although there have been many reports of Sc-based material,but there is no studies on the structure control and optical properties of Sc-based material in oxyfluoride glass ceramic.In this paper,Sc-based oxyfluoride glass ceramics doped with rare earth/transition metal ions were first studied systematically on the structure control of Sc-based nanocrystals,optical properties and related mechanisms of activator.The main contents and research results of this paper are as follows:The first chapter as the introduction of this paper mainly introduces the basic knowledge and research background needed in the research process,which include basic introduction and luminescence principle of rare earth/transition metal ions,introduction of oxyfluoride glass ceramic materials and research status of Sc-based luminescent materials.The second chapter mainly studies the growth relations and optical properties of Na Yb F4 and Na3 Sc F6 nanocrystalline in glass ceramic.With a large number of experiments,we found the crystallization phase transit from cubic Na Yb F4 to monoclinic Na3 Sc F6,through simple control the Na+ content and F/Na ratio in glass component.In addition,based on the transformation of the luminescence intensity with Er3+-doping analyzed the optical properties of rare earth ions in different crystalline phases.In the end,we probed that the rare earth ions is difficult to enter Na3 Sc F6 nanocrystalline with Eu3+ structure probe.In chapter three,transparent glass ceramics containing single-phase KSc2F7 nanocrystals were successfully prepared through composition design and glass structure optimization.Furthermore,microstructure,morphologic features and optical properties are well studied by X-ray powder diffraction(XRD),high resolution electron microscopy(TEM/HRTEM)and fluorescence spectrometer.Characterization findings different from other matrix materials,some rare earth ions with small ion radius can be used as nucleating agents to promote nucleation and growth of KSc2F7 particles.KSc2F7 nanocrystals cannot be precipitated out when doping without rare earth ion doping or with large ion radius of rare earth ions.Otherwise,after heat treatment,lanthanide ions(Er3+,Ho3+,Tm3+)as activators entered the precipitated KSc2F7 nanocrystals and the luminescence intensity of the glass ceramics was significantly enhanced compared with that of the precursor glass.Further study found the precursor glass had amorphous regions enriched with K/Sc/Ln/F ion clusters,KLn Fx nanocrystalline grew prior to KSc2F7 nucleation with the increase of heat treatment temperature,then some KLn Fx nanocrystalline Ln3+ was replaced by Sc3+ to form KSc2F7 nanocrystalline.In chapter four,the structure and optical properties of dual-phases glass ceramics containing KSc2F7 and KYF4/KYb2F7/KLu2F7 nanocrystalline were studied.Benefited by the selective doping of Ln3+ in KSc2F7 crystals,three kinds of dual-phase glass ceramic systems(Sc-Yb,Sc-Lu and Sc-Y)were prepared with different Sc-Ln ratios through the competitive growth relationship between Sc-based fluoride and Ln-based fluoride.With different Ln3+ doped conditions,we first report that tunable multicolor upconversion luminescence can be achieved through diversified regulatory approaches,such as adjustment of the dual-phase ratio,selective separation of Ln3+ dopants,and alteration of incident pumping laser.In the end,as a proof-of-concept experiment,the application of dual-phase glass as a color converter in 980 nm laser-driven upconverting lighting is demonstrated.Chapter five investigated the influence of Sc3+ doping ratio on the structure and optical properties of Mn2+ ions by using the manganese-doped precursor glass as the matrix.It was found that the cationic field strength of rare earth ions caused the change in the structure of the glass network,which led to the transform of the coordination environment of manganese ions,resulting in the red-shift phenomenon from green to orange emission.Finally,the main contents and application prospects of this paper are respectively summarized and prospected.