| Recently,glass ceramic(GC)luminescent materials have attracted great attentions as they have excellent mechanical properties and optical performance.Various GCs have been developed for potential applications in solid-state laser,three-dimensional display.Currently,GCs were demonstrated to have another promising application in noncontact optical thermometers as they can overcome the shortcomings of inaccuracy and long response time of the conventional contact temperature sensors and are usable in electromagnetically and/or thermally harsh surroundings.Generally,the fluorescence intensity ratio(FIR)of lanthanide(Ln3+)ions and fluorescence lifetime of transition metal(TM)ions,which are temperature-sensitive,were adopted to detect temperature since these two parameters are independent of shapes and sizes of samples.The purposes of our research on the glass ceramics doped with RE ions or TM ions are to explore its microstructure,and to analyze the possibility in noncontact optical thermometers.The research results are generally presented as follows:The first chapter mainly introduces the research background and preparation and characterization of the glass ceramic materials,as well as several methods of noncontact temperature sensing based on the fluorescence intensity ratio and luminescence decay curves,respectively.Furthermore,the basic knowledge and principles of RE and TM ions are also illustrated in this chapter.In chapter two,the structure of rare earth doped glass ceramic and temperature detection performance are well studied.Two analyses on the Gd-based oxyfluoride glass ceramics are explored:(1)Hexagonal to orthorhombic phase transformation of Gd F3 nanocrystals in the bulk glass ceramics was achieved through alkaline-earth/alkali-metal doping and crystallization temperature controlling.(2)Hexagonal Gd F3 was precipitated from glass matrix with high F-/O2-ratio while cubic Na Gd F4 and hexagonal Na Gd F4 were sequentially precipitated from glass matrix with decrease of F-/O2-ratio.On the other hand,the optical thermometry based on the the thermally coupled energy levels of the Er3+ ions is presented by means of the fluorescence intensity ratio in all the phases.What's more,oxyfluoride glass ceramic containing ?-YF3 nanocrystals are successfully prepared via Melt-quenching method in air atmosphere.Different RE ions are doped to investigated their luminescence performance and the application on optical thermometry.TM ion is also an excellent luminescence center except for RE ion.Owing to the overlapping emissions from single luminescence center,which will result in significant inaccuracies for temperatrure determination,RE/TM ions co-doped glass ceramics are prepared in chapter three.Yb3+/Ln3+/Cr3+(Ln=Er,Ho)tri-doped Li Ga5O8 and Eu2+/Cr3+ co-doped Gd F3/Ga2O3 dual-phase glass ceramics were fabricated via a melt-quenching route and subsequent glass crystallization.In the former GC system,Intense Cr3+ upconversion luminescence assigned to 2E?4A2 transition was observed upon 980 nm laser excitation.Importantly,the investigated glass ceramics presented temperature-dependent upconversion fluorescence intensity ratios for the Er3+ 2H11/2/4S3/2 thermally coupled states as well as the Cr3+/Ln3+ non-thermally coupled states and temperature-sensitive upconversion decays of Cr3+ 2E/4A2 thermally coupled states,enabling their promising applications in self-calibrated multi-modal temperature sensing.While in the latter one,Eu2+/Cr3+ emitting centers were evidenced to separately incorporate into Eu F3 and Ga2O3 crystalline lattices,respectively.As a result,temperature determination with high sensitivity of 0.8% K-1,large energy gap of 8500 cm-1 realized by taking advantage of fluorescence intensity ratio between Eu2+ and Cr3+ as detecting parameter,which exhibited linear dependence on temperature.Finally,the main content of this paper are summarized. |
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