Preparation And Spectrum Property Of Cr³⁺ Doped Oxide Phosphors

In modern production and life,luminescent materials,as a necessary part of human production and life,have been explored and studied by researchers.For example,as a green light source,the white LED is concerned because of its advantages of portability,long life cycle,high luminous efficiency,easy storage,low cost and so on.There are also some light conversion materials can play an important role in agricultural production.So the excellent phosphor material has a great effect on these applications.Because of its special electronic layer structure and high price compared with rare earth elements,the transition metal Cr has been playing an important role in the synthesis of red phosphors.In this paper,the high temperature solid state method and sol-gel high temperature solid-state method were used to prepare the Al₂O₃:Cr³⁺fluorescent materials and Mg_0.388Al_2.408O₄:Cr³⁺fluorescent materials respectively.The influence factors of Cr³⁺doping concentration,burning temperature and holding time were discussed.Finally,the synthesized samples were analyzed by X-ray diffraction?XRD?,excitation spectrum,emission spectrum,fluorescence lifetime decay curve and color coordinates,and the following conclusions were obtained:?1?The XRD of Al₂O₃:Cr³⁺fluorescent material has no change compared with the standard card under different Cr³⁺doping concentration.The intensity of the excitation spectrum and the emission spectrum will change with the change of the concentration,but the peak position will not change,which are 409nm,546nm,693.6nm and 694.8nm,respectively.Under the condition of fixed doping concentration,the best burning temperature appears at 1300?.The optimum holding time is 3h at a fixed doping concentration and temperature.The fluorescence lifetime is about 4.32641ms.The CIE coordinate of Al₂O₃:Cr³⁺phosphor at 1%doping concentration is?0.7345,0.2657?.The position of this point is in the red boundary region,which indicates that Al₂O₃:Cr³⁺phosphor emits red light,which is consistent with the emission peak of phosphor at 694.9nm.?2?Compared with the standard card,the Mg_0.388Al_2.408O₄:Cr³⁺sample has no extra heterophase.When excited by 407nm excitation light,it can emit red and near-infrared light in the range of 670nm to 750nm.With the doping concentration of Cr³⁺from 1%to 3%,the emission peak position of the samples did not change,and there was a strong emission peak at 689nm.The optimum doping concentration of Cr³⁺is 1%.Two excitation bands,380nm⁴50nm and 520nm⁶00nm,were obtained from 689nm emission light.The central wavelengths were 407nm and552nm,respectively.The fluorescence lifetime is about 4.8255ms.The color coordinates are?0.7343,0.2657?,which are located at the edge of the red boundary,which is consistent with the emission peak of the phosphor at 688nm.