物理化学学报 >> 2006, Vol. 22 >> Issue (10): 1291-1295.doi: 10.3866/PKU.WHXB20061023

研究简报 上一篇    下一篇

ZnGa2O4:Cr3+红色荧光粉的光致及电致发光性能

乔彬;唐子龙;张中太;陈雷   

  1. 清华大学材料科学与工程系, 新型陶瓷与精细工艺国家重点实验室, 北京 100084
  • 收稿日期:2006-03-31 修回日期:2006-05-31 发布日期:2006-10-11
  • 通讯作者: 乔彬 E-mail:qiaobin98@mails.tsinghua.edu.cn

Photoluminescent and Electroluminescent Characteristics of ZnGa2O4:Cr3+ Red Phosphor

QIAO Bin;TANG Zi-Long;ZHANG Zhong-Tai;CHEN Lei   

  1. State Key Laboratory of New Ceramics and Fine Processing, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, P. R. China
  • Received:2006-03-31 Revised:2006-05-31 Published:2006-10-11
  • Contact: QIAO Bin E-mail:qiaobin98@mails.tsinghua.edu.cn

摘要: 采用柠檬酸络合溶胶-凝胶法合成ZnGa2O4:Cr3+红色荧光粉, 在空气气氛中1000 ℃煅烧得到ZnGa2O4单相. 对粉体进行X射线光电子能谱(XPS)和电子顺磁共振(EPR)测试, 结果显示, 在空气气氛中煅烧, 铬离子以三价形式存在(Cr3+), 未出现高价铬离子(Cr5+, Cr6+). Cr3+取代Ga3+占据八面体格位, 位于695 nm的红光发射带属于Cr3+的2E-4A2跃迁. Cr3+的激发带与基质发射带间有大面积重叠, 两者间存在有效的能量传递. 利用丝网印刷方法制成电致发光器件, 与硫化物电致发光器件相似, ZnGa2O4:Cr3+电致发光器件的亮度与电压满足L=L0exp(−bV−1/2)关系, 且亮度与频率成正比. 器件的Q−V曲线为闭合回路, 发光效率η约为13 lm•W−1.

关键词: ZnGa2O4, Cr3+, 柠檬酸溶胶-凝胶法, 光致发光, 电致发光

Abstract: ZnGa2O4:Cr3+ red phosphors were synthesized by citric-gel method. Typical spinel-phase ZnGa2O4 could be attained after calcined at 1000 ℃ in air ambient. According to the results of XPS and EPR, it could be deduced that Cr3+ ions were dominant in the lattice and it could not be oxidized to Cr5+ or Cr6+ after calcined in air. The emission of Cr3+ at 695 nm is originated from the transition of 2E-4A2. And due to the large overlap between absorption band of Cr3+ and emission band of the host, Cr3+ could obtain the excitation energy from the host via the effective energy transfer. The electroluminescent device was fabricated by screen printing utilizing ZnGa2O4:Cr3+ as the phosphor layer. Luminance (L) versus voltage (V) of the device match the well-known equation of L=L0exp(−bV−1/2) and the luminance increase proportionally with frequency due to the increase of excitation probability of host lattice or Cr3+ centers. The diagram of charge density (Q) versus applied voltage (V) is based on a conventional Sawyer-Tower circuit. At 280 V and 1000 Hz, the luminance and luminous efficiency of the fabricated powder EL device are about 1.0 cd•m−2 and 13 lm•W−1, respectively.

Key words: ZnGa2O4, Cr3+, Citrate-gel method, Photoluminescence, Electroluminescence