无机材料学报 ›› 2021, Vol. 36 ›› Issue (5): 513-520.DOI: 10.15541/jim20200386

• 研究论文 • 上一篇    下一篇

调控Al2O3晶型控制MgAl2O4:Mn4+荧光粉中Mn价态研究

王兆武1(), 姬海鹏1(), 王飞翔1, 侯星慧1, 易莎莎1, 周颖1, 陈德良1,2()   

  1. 1.郑州大学 材料科学与工程学院, 郑州 450001
    2.东莞理工学院 材料科学与工程学院, 东莞 523830
  • 收稿日期:2020-07-09 修回日期:2020-08-26 出版日期:2021-05-20 网络出版日期:2021-04-19
  • 通讯作者: 姬海鹏, 讲师. E-mail: jihp@zzu.edu.cn; 陈德良, 教授. E-mail: dlchen@zzu.edu.cn
  • 作者简介:王兆武(1985-), 男, 博士研究生. E-mail:smithen0504@gs.zzu.edu.cn
  • 基金资助:
    国家自然科学基金(51902291);中国博士后科学基金(2019M662524);河南省博士后科研项目(19030025);河南省高校科技创新团队(19IRTSTHN028)

Valence State Control of Manganese in MgAl2O4:Mn4+ Phosphor by Varying the Al2O3 Crystal Form

WANG Zhaowu1(), JI Haipeng1(), WANG Feixiang1, HOU Xinghui1, YI Shasha1, ZHOU Ying1, CHEN Deliang1,2()   

  1. 1. School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, China
    2. School of Materials Science and Engineering, Dongguan University of Technology, Dongguan 523808, China
  • Received:2020-07-09 Revised:2020-08-26 Published:2021-05-20 Online:2021-04-19
  • Contact: JI Haipeng, lecturer. E-mail: jihp@zzu.edu.cn; CHEN Deliang, professor. E-mail: dlchen@zzu.edu.cn
  • About author:WANG Zhaowu(1985-), male, PhD candidate. E-mail:smithen0504@gs.zzu.edu.cn
  • Supported by:
    National Natural Science Foundation of China(51902291);China Postdoctoral Science Foundation(2019M662524);Post Doctoral Research Sponsorship in Henan Province(19030025);Program for Innovative Research Team (in Science and Technology) in University of Henan Province(19IRTSTHN028)

摘要:

Mn4+激活红光荧光粉是白光半导体发光二极管(wLEDs)领域当前研究热点之一。Mn4+离子2E→4A2跃迁在铝酸盐中的最短发光波长是在MgAl2O4中实现的651 nm发光, 由于其结构中含有形成四面体或八面体配位的两种阳离子格位(Mg2+/Al3+), 易造成所掺杂锰元素存在多种价态(+2/+4/+3等)。本研究通过改变起始原料中Al2O3的晶型(γ/α比例)及退火处理来调控锰离子在MgAl2O4晶格中的占据格位, 对其主要存在价态实现调控。采用荧光光谱和紫外-可见-近红外漫反射光谱技术来表征所合成荧光粉中Mn离子的价态及其演变。研究发现, 高α/(α+γ)比铝源促进Mn2+形成, 而低α/(α+γ)比铝源促进Mn4+形成。通过使用高活性纳米γ-Al2O3为铝源, 有效抑制了锰离子在MgAl2O4中Mg2+格位的占据及Mn2+离子的形成, 经空气中1550 ℃保温5 h的一次高温热处理即可制备出在可见光区只有Mn4+红光发光的高纯高亮度MgAl2O4:Mn4+荧光粉。氧化铝晶型影响锰离子掺杂格位和掺杂价态的本质规律是: 氧化铝活性决定实际固溶掺杂反应步骤, 进而影响锰离子掺杂格位和价态。本研究提出的反应步骤调控作为反应气氛、电荷补偿剂、反应温度三种调控方法外的一种新方法, 为Mn4+激活铝酸盐荧光粉中锰离子掺杂价态调控提供了新思路。

关键词: Mn4+, 白光LEDs, 红光荧光粉, 价态调控

Abstract:

Mn4+ activated red phosphor is one of the current research hot-spots in the field of white light emitting diodes (wLEDs). The shortest emission of Mn4+ 2E→4A2 transition in aluminate is 651 nm realized in MgAl2O4, but the doped manganese ions exists in multiple valence states (+2/+4/+3, etc.) due to the fact that there exist two cationic sites (Mg2+/Al3+) forming tetrahedron or octahedron coordination in the spinel structure. In this study, variation of the Al2O3 polymorphs (γ/α ratio) in the starting materials and post-annealing were used to control the doping sites and valence state of manganese ions in the MgAl2O4 structure. The results show that a high α/(α+γ) ratio of starting Al2O3 favors the formation of Mn2+ while a low α/(α+γ) ratio of starting Al2O3 favors the formation of Mn4+ dopant. By using highly active nano-γ-Al2O3 as the Al3+-bearing source, the occupancy of manganese ions in the Mg2+ site and the formation of Mn2+ valence state were effectively suppressed. Bright and pure MgAl2O4:Mn4+ phosphors in which only the red luminescence from Mn4+ was observed in the visible spectral region were successfully prepared via once heat treatment at 1550 ℃ for 5 h in air. The intrinsic reason for the dependence of manganese doping valence state on the Al2O3 polymorph lies in that the reactivity of Al2O3 determined the sequences of doping reactions and then the doping site/valence of manganese ions in MgAl2O4:Mn. All the above data demonstrated that the control of reaction sequences was a new method to regulate the valence state of manganese in aluminate phosphors.

Key words: Mn4+, white LEDs, red-emitting phosphor, valence state control

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