Study on ZnGab>2b>Ob>4b>:Cr³⁺ a.c. powder electroluminescent device

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• 作者：B. Qiao ; Z.L. Tang ; Z.T. Zhang ; L. Chen
• 关键词：Phosphor ; Electroluminescence ; ZnGab>2b>Ob>4b> ; Cr³⁺
• 刊名：Materials Letters
• 出版年：2007
• 期刊代码：59_0167577x
• 类别：ms
• 出版时间：January 2007
• 卷：61
• 期：2
• 页码：401-404
• 文件大小：467 K

摘要

An a.c. powder electroluminescent (EL) device using ZnGab>2b>Ob>4b>:Cr³⁺ phosphor was fabricated by the screen printing method. Optical and electrical properties of the device were investigated. The fabricated device shows a red emission at 695 nm driven by the a.c. voltage. The emission is attributed to the energy transfer from hot electrons to Cr³⁺ centers via self-activated Ga–O groups. Luminance (L) versus voltage (V) matches the well-known equation of L = Lb>0b>exp(− bV ^{− 1 / 2}) and luminance increases proportionally with frequency due to the increase of excitation probability of host lattice or Cr³⁺ centers. The diagram of the charge density (Q) versus applied voltage (V) is based on a conventional Sawyer–Tower circuit. At 280 V and 1000 Hz, the luminance and the luminous efficiency of the fabricated powder EL device are about 1.0 cd/m² and 13 lm/W, respectively. And under the high field, the device fabricated with the oxide-based phosphor of ZnGab>2b>Ob>4b>:Cr³⁺ shows excellent stability in comparison with the conventional sulfide powder EL device.