摘要
采用一种较为温和的水热法成功地制备出一种新型白光LED用红色Sr_yCa_(1-x-y)WO_4:xEu^(3+)(x=0,0.05;y=0,0.01,0.02,0.03,0.05)荧光粉,基于第一性原理对CaWO_4和Sr_(0.02)Ca_(0.98)WO_4的电子结构进行了理论分析,通过X射线衍射、Rietveld精修和荧光光谱对样品的物相结构和发光性能进行了研究。计算结果表明:CaWO_4、Sr_(0.02)Ca_(0.98)WO_4晶体都是一种直接带隙半导体,禁带宽度分别为4.077eV和4.080eV.XRD和精修结果表明了所制备的荧光粉是空间群为I41/a(88)纯四方相的白钨矿结构,Eu^(3+)和Sr^(2+)成功的掺杂到CaWO_4晶格中取代了Ca位.荧光光谱结果表明:当x=0.05,y=0.02时,Sr_yCa_(1-x-y)WO_4:xEu^(3+)系列荧光粉在617nm处Eu^(3+)的~5D_0→~7F_2电偶极跃迁发射最强,并且在近紫外(397nm)和蓝光区域(467nm)处都能被有效激发,Sr^(2+)引入到CaWO_4:0.05Eu^(3+)中可以通过改变Eu^(3+)格位周围对称性从而增强红光发射.这些结果表明Sr_(0.02)CaWO_4:0.05Eu^(3+)荧光粉可以作为一种有前景的白光LED用红色荧光粉.
A series of new red SryCa1-x-yW04:xEu^3+(x=0,0.05;y=0,0.01,0.02,0.03,0.05)phosphors of white LEDs were successfully prepared by a mild hydrothermal method.The electronic structure of CaWO4 and Sr0.02Ca0.98WO4 was calculated and analyzed by firstprinciples.The phase structure and luminescence properties of the samples were studied by X-ray diffraction,Rietveld refinement and fluorescence spectroscopy.The calculation results show that the CaW04 and Sr0.02Ca0.93W04 crystals are all direct band gap semiconductors with band gaps of 4.077 eV and 4.080 eV,respectively.XRD and Rietveld refinement show that the prepared phosphors is a scheelite structure with a space group of I41/a(88)pure tetragonal phase.Eu^3+and Sr^2+are successfully doped into the CaW04 lattice to replace the Ca site.Fluorescence spectroscopy results show that the SryCa1-x-yWO4:xEu^3+phosphors emit the strongest 5D0→7F2 electric dipole transition of Eu^3+at 617 nm when x=0.05,y=0.02.Meanwhile,it can be effectively excited in the near ultraviolet(397 nm)and blue regions(467 nm).And the introduction of Sr^2+into CaWO4:0.05Eu^3+will change the symmetry around the Eu^3+lattice to enhance red emission.These results indicate that the phosphor is a promising red phosphor for use in W-LEDs.
作者
白少杰
刘运
刘丁菡
王凯
朱毅
王蓉
张富春
BAI Shao-jie;LIU Yun;LIU Ding-han;WANG Kai;ZHU Yi;WANG Rong;ZHANG Fu-chun(School of Materials Science and Engineering,Shaanxi University of Science&Technology,Xi’an 710021,China;College of Electrical and Information Engineerings Shaanxi University of Science&Technology,Xi'an 710021,China;College of Physics and Electronic Information,Yan'an University,Yan'an 716000,China)
出处
《陕西科技大学学报》
CAS
2019年第1期101-107,共7页
Journal of Shaanxi University of Science & Technology
基金
国家自然科学基金项目(51272148)
