Sensitized Luminescence And Solid Solution Effect Of Ca_1-zM_zTiO₃:xEu³⁺,yBi³⁺

As a solid light source,white-light emitting diodes?W-LED?z can offer benefits such as high brightness,low power consumption,long lifetime,small size,light weight,high luminous efficiency,quick response,non-radiation and environmentally friendly charActeristics.It has been an inevitable tendency that W-LEDs will replAce florescent lamp,incandescent light and high intensity discharge,and develope a new generation of light source.The present commercial W-LEDs is to combine a blue LED chip with yellow phosphors.However,the as-obtained white light shows color rendering index deficiency and high color temperature.Another approAch might solve these problems by using a near UV?NUV?LED chip coated with three?blue,green and red?emitting phosphors to generate desired warm white light.In recent years,great efforts have been made to investigate high efficiency phosphors excited by NUV among which the blue and green ones have been relatively mature.The luminous intensity,quantum efficiencies and stabilities of the existing red phosphors are still not enough to meet the demands in LED systems.Therefore,chemical and thermal stable red emitting phosphors with high luminescent efficiency stimulated by NUV have attrActed widely attention.Alkaline earth titanate MTiO₃?M = Ca,Sr and Ba?is a good luminescent material matrix with chemical stability and appropriate band gap.The excitation spectrum of CaTiO₃:Eu³⁺?CTE?covers the range from NUV to visible light.Consequently,the phosphors can be excited by NUV and blue light and produce high-efficiency red light emission.Besides,CTE can be made into novel red shine ceramic because of well thermal stability and mechanical strength.Thus,there are important theoretical significance and application value to study in rare earth ions doped CaTiO₃ phosphors.In this article,CTE phosphors were prepared by sol-gel method for avoidance of drawbAcks of lower intensity,longer fire time and more doping ions by traditional high temperature solid method.Meanwhile,in order to improve the luminescent properties,sensitizers and solid solutions for Eu³⁺ ions Activated CaTiO₃ phosphors were also studied.1.Preparation,charActerization and luminescent properties of CaTiO₃:Eu³⁺CTE phosphors were prepared by sol-gel method and the effects of calcination temperature and time on the phase compositions and luminescent properties were also investigated.The result showed that phosphors with fine particles,pure phase and well luminescent intensity were obtained after firing at 1400 ? for 4 h which can be excited by UV and blue light and effectively emit red light at 615 nm.2.Sensitized luminescence of CaTiO₃:Eu³⁺ with co-doped ionsA serials of sensitizers were tested and the effects of different ionsand doping concentrations on the optical properties of CaTiO₃:Eu³⁺ were studied.The result showed that the luminescent properties of the phosphors enhanced to varing degrees in the presence of Bi³⁺,Tb³⁺ and Sm³⁺ sensitizer ions among which the former was the best.3.Influence of solid solution on the luminescent properties of phosphors Ca1-zMzTiO₃:Eu³⁺,Bi³⁺With Bi³⁺ as sensitize ions,the effect of solid solutions doped with Mg²⁺,Sr²⁺,Ba²⁺ and Zn²⁺,respectively,on the optical properties was investigated.The result showed that Mg²⁺ ions would not change the structure and composition of the host material and meanwhile contributed to improve the optical property of CaTiO₃:Eu³⁺,Bi³⁺.But the first three metal ions played roles of quench.