Study On Properties Of Rare Earth And Transition Metal Ions Doped Gallogermanates Luminescence Materials And Exploration Of Their New Applications

Under the current trend of energy shortage and energy conservation and emission reduction,low-energy light sources are the current research hotspot.White light LED?light emitting diode?is expected to replace traditional lighting as a new generation of green light source because of its long life,high efficiency,low energy consumption,energy saving and environmental protection.Nowadays,there are two ways to implement commercialized white LEDs.First,the yellow phosphor(YAG:Ce³⁺)is excited by an InGaN-based blue LED chip to obtain yellow light,and mixed with blue light that is not completely absorbed to emit white light.Another method is to use a near-ultraviolet LED chip to excite the three primary color phosphors to obtain three colors of red,green and blue light to combine white light.The former has a low color rendering index due to the lack of red light components,and the latter has low efficiency due to the low luminous efficiency of the existing red phosphors.Therefore,the research and development of new red phosphors is the focus of current research.In addition,the red light in the trichromatic phosphor has a strong reabsorption of blue light,resulting in relatively low luminous efficiency.Whether it is white light combined with blue LED and yellow phosphor,or white light with three primary color phosphors will have color drift?The high temperature generated by the device after a long-time working changes the relative intensity of the three primary colors,thereby changing the color of the light?.Therefore,single-substrate white light-emitting luminescence materials are also a hot spot of research.Parts of the inorganic luminescent materials also have long-persistent luminescence characteristics.Such materials show great potential in bioimaging,medical diagnosis,etc.However,the long-persistent luminescence mechanism has not been fully studied,and the long-persistent luminescence performance still has a lot of space for improvement.Due to the sensitive properties of luminescent materials such as temperature sensitivity and luminescent environment,sensors based on inorganic luminescent materials are also being explored,which is the future research focus of inorganic luminescent materials.In this paper,we mainly chose several gallogermanates as research objects,namely Sr₂Ga₃LaGe₃O₁₄,and La₂MgGeO₆ and Sr₂MgGe₂O₇.Firstly,Sr₂Ga₃LaGe₃O₁₄ host and Sr₂Ga₃LaGe₃O₁₄:Dy³⁺single host white light emitting luminescence material were prepared and studied.And Sr₂Ga₃LaGe₃O₁₄:Eu³⁺deep red luminescence materials also were prepared and studied.In addition,the properties the defect sources of La₂MgGeO₆:Cr³⁺near-infrared long-persistent luminescent materials were studied.The potential application value of La₂MgGeO₆:Bi³⁺,Sm³⁺materials on color-temperature indicators were studied.Finally,we studied the relationship between the structure change and the change of properties of the citrate luminescent material Sr₂MgGe₂O₇:Pb²⁺and aluminate Sr₂MgAl₂₂O₃₆:Eu²⁺by atomic substitution method.The following researches progress has been made:1.Sr₂Ga₃LaGe₃O₁₄ and Sr₂Ga₃LaGe₃O₁₄:Dy³⁺materials were synthesized by high temperature solid phase reaction.The host emits blue-white light under UV excitation,and the excitation spectrum is a narrow band in the 200-300 nm regions due to the Ga³⁺-O^2-charge transfer transition.Dy³⁺in the Sr₂Ga₃LaGe₃O₁₄:Dy³⁺cannot be sensitized by the host.Dy³⁺emits white light emission.The quenching concentration of Dy³⁺is 0.06 and multipolar interaction is the main quenching mechanism.2.The Sr₂Ga₃LaGe₃O₁₄:Eu³⁺deep red-emitting materials were synthesized by high temperature solid phase reaction.The deep red-emitting materials can be effectively excited by ultraviolet(Eu³⁺-O^2-charge transfer)and near-ultraviolet light.The Eu³⁺ions did not undergo concentration quenching until all of the La³⁺ions were replaced by Eu³⁺.3.The La₂MgGeO₆:Cr³⁺near-infrared long-persistent luminescence materials were synthesized by high-temperature solid-state reaction method.The remaining glow properties were optimized by co-doping Dy³⁺and Sm³⁺.The long-persistent luminescence time can reach tens of minutes.Studies have shown that the materials have two traps,one source derived from the host,and anthor one derived from the introduced ions.4.La₂MgGeO₆:Bi³⁺,Sm³⁺materials were synthesized by high temperature solid phase reaction.The corresponding relationship between the color of the luminescence color and the temperature was studied,indicating it has great potentiality on the color-temperature indicator.5.The relationship between the crystal structure and luminescence properties of Pb²⁺doped germanate Sr₂MgGe₂O₇ and Eu²⁺doped aluminate Sr₂MgAl₂₂O₃₆ under atomic substitution method?here,Sr is replaced by Ba?is studied for the first time.