Synthesis And Luminescent Properties Of High Pure Nitride Phosphors Prepared Under Atmospheric Pressure

Because of its stable structure and strong covalent existence,having the better physical and chemical stability and optical conversion efficiency than the traditional phosphors,nitride phosphors is one of the most promising phosphors for the application.However,the synthesis of high pure nitride phosphors is usually related to high temperature?1600-1800 ??,and/or high pressure?0.1-10 MPa?,as well as the raw materials are expensive,unstable and the equipment conditions are harsh,which greatly limits its further application and development.In recent years,around the preparation and synthetic methods of the nitride phosphors,researchers carried out a series of meaningful research work from precursor materials,preparation and synthetic techniques and equipments,including the preparation and synthesis of nitride phosphors under atmospheric pressure.While the incomplete reaction,poor crystallization under the atmospheric pressure,it is difficult to obtain high pure nitride phosphors.In view of this,this thesis explores the preparation and synthesis of high pure nitride phosphors materials under atmospheric pressure by high temperature solid-state method and carbon thermal reduction method and its luminescent properties were investigated.The specific research achievements are as follows:A.CaAlSiN₃:Eu²⁺/Ce³⁺ phosphors were synthesized under atmospheric pressure at a related low temperature of 1550 ?,via CaH₂,AlN,Si₃N₄,EuF₃,CeF₃ by high temperature solid-state reaction.The properties?phase,fluorescence,thermal stability,color coordinates,etc.?of the samples were obtained.The effect of Eu²⁺ ion on the luminescent properties of cerium doped CaAlSiN₃ and energy transfer of Ce³⁺-Eu²⁺ were obtained.B.CaAlSiN₃:Eu²⁺ phosphors were synthesized under atmospheric pressure,at a related low temperature of 1550 ?,via AlN,CaH₂,Si₃N₄,Eu₂O₃ and C?graphite powder?,by carbon thermal reduction method.The effect of the concentration of carbon on the properties of the product,and the effect of the concentration of Eu²⁺ on the phase and luminescent properties of the products with the ratio of fixed carbon to oxygen were obtained.C.In the light of AlN impurity phase are existed in the CaAlSiN₃ based phosphors materials prepared and synthesized under atmospheric pressure by high temperature solidstate method and carbon thermal reduction method.We carried out the research work of inhibition of AlN impurity phases in order to enhance the luminous performance of CaAlSiN₃ based phosphors.Through the deviation of stoichiometry ratio of AlN raw material and adding SrF₂ flux to examined the inhibition of AlN impurity phase and the improvement of luminescence performance.Nitride phosphors with high pure phase and good luminescent properties were prepared and synthesized under atmospheric pressure through optimizing AlN raw material ratio and flux material.D.Ca₂Si₅N₈/CaSiN₂ phosphors were synthesized under atmospheric pressure at a related low temperature of 1550 ?,via CaH₂,Si₃N₄,EuF₃ by high temperature solid-state reaction,and the properties of phase,fluorescence spectrum,diffuse reflectance and thermal stability were characterized and analyzed.