Study And Application Of Crystal Structure,Control And Properties Of Rare Earth Ions Doped Aluminosilicate Phosphors

Recently,white light-emitting diode?w-LED?is replacing the original lighting source gurgually in people's daily life,due to the advantage of high luminous efficiency,environmental protection,long service time and so on.At present,commercial w-LED is mainly composed by mixing the yellow phosphor Y₃Al₅O₁₂:Ce³⁺with blue LED chip GaInN.These series w-LED may have the disadvantage of a lower color rendering index,a higher color temperature because of the lack of red light emission,and the emission color would change with the using time larger.In order to avoid these problems,researchers are currently studying the use of ultraviolet LED chip combined with a single matrix white fluorescent powder to achieve w-LED,which not only avoids the chip's influence on the properties of fluorescent powder,but also avoids the process of photon reabsorption between different powders.Because of its simple synthesis method,stable physical and chemical properties,and cheap and easy materials,silica-aluminate is often used in phosphor substrate.In this paper,two different silicon-aluminate substrates were selected to achieve polychromatic luminescence of phosphors by doping cerium,terbium,europium and other rare earth ions.The relationship between matrix structure and luminescence performance was studied in detail by Rietveld refinement,first-principles calculation,temperature variation spectrum and other research methods.The research results are as follows:1.A series of Ca₂₀Al₂₆Mg₃Si₃O₆₈:Ce³⁺/Tb³⁺phosphors were synthesized by high temperature solid phase method.By changing the concentration of Tb³⁺ions doped to achieve multicolor luminescence,the energy transfer mode between Ce³⁺and Tb³⁺ions was discussed,the influence of Tb³⁺ions on the luminescence center location of Ce³⁺ions was discussed in detail,and the performance of LED devices of this series of samples was evaluated.2.Following the content of chapter 2,a series of Ca₂₀Al₂₆Mg₃Si₃O₆₈ co-doped Eu²⁺/Eu³⁺phosphors were synthesized,the presence of Eu³⁺ions was detected by the emission spectrum of the samples,and the coexistence of Eu²⁺and Eu³⁺was explained by X-ray photoelectron spectroscopy,variational temperature spectrum and theoretical analysis.Combined with the appropriate uv-LED chip to prepare the device and conduct the LED device performance test.3.A series of Ca(Mg_0.8Al_0.2)(Si_1.8Al_0.2)O₆:Ce³⁺/Tb³⁺phosphors were synthesized by high temperature solid phase method.The effects of partial substitution of Al³⁺ions by Mg²⁺and Si⁴⁺ions on the structure and luminescence properties of Ce³⁺ions were systematically studied by Rietveld finishing,theoretical calculation,and uv diffusion spectroscopy.By adjusting the concentration of Tb³⁺ions,polychromatic luminescence was achieved.Suitable samples were selected and combined with uv-LED chip to prepare the device,and the device performance was tested.