摘要
可被蓝光激发的高热稳定性红色荧光粉是制作高性能白光二极管(WLED)的关键材料.研究发现,Ce^(3+)掺杂的SrLaScO_(4)(SLO:Ce^(3+))荧光粉在440 nm激发下呈现峰值为640 nm的反常宽带红光发射.光谱学和结构分析证实Ce^(3+)离子在SLO中进入[LaO_(8)]多面体,产生强的晶体场劈裂和较大的Stokes位移,实现了比Eu^(2+)更低能量的红光发射.我们还设计并揭示了一种电荷转移相互作用的策略:在Sc^(3+)位置引入电负性较大的Ga^(3+),Ga^(3+)可以吸引更多邻位配合基团的电荷,以减少导带底部的电子占用而扩大带隙.Sc/Ga取代有效地抑制了热激活电离过程,使SrLa(Sc,Ga)O_(4):Ce^(3+)的热稳定性获得了显著提升,即在150℃的发光强度比(相对于20℃)从15%提升至31%.本研究为发现具有良好热稳定性的新型Ce^(3+)掺杂红色荧光粉提供了有效的设计原则.
Blue-light-excitable red-emitting phosphors with high thermal stability are essential for fabricating white light-emitting diodes(WLEDs).Herein,Ce^(3+)-doped SrLaScO4(SLO:Ce^(3+))phosphor is discovered to have an abnormal red emission band centered at 640 nm when excited at 440 nm.Spectroscopy and structural analyses confirm that Ce^(3+)ions occupy the[LaO_(8)]polyhedrons competitively,generating a strong crystal field splitting and a large Stokes shift to produce a red emission.To further restrict the thermal quenching of SLO:Ce^(3+),charge-transfer engineering is implemented by incorporating a large electronegative Ga^(3+)in the Sc3+site,which can attract more charges from nearby coordinating groups to decrease the electronic occupation at the bottom of the conduction band and thereby enlarge the band gap.Sc/Ga substitution in SrLa(Sc,Ga)O_(4):Ce^(3+)enhances the thermal stability by increasing the intensity ratio from 15%to 31%at 150℃ compared with 20℃.This is attributed to the efficient suppression of the thermally stimulated ionization process.This study presents a general design principle for discovering novel Ce^(3+)-doped red phosphors with good thermal stability for WLED applications.
作者
杨至雨
赵逸飞
Jumpei Ueda
Maxim S.Molokeev
尚蒙蒙
夏志国
Zhiyu Yang;Yifei Zhao;Jumpei Ueda;Maxim S.Molokeev;Mengmeng Shang;Zhiguo Xia(State Key Laboratory of Luminescent Materials and Devices,Guangdong Provincial Key Laboratory of Fiber Laser Materials and Applied Techniques,Guangdong Engineering Technology Research and Development Centre of Special Optical Fibre Materials and Devices,School of Materials Science and Engineering,South China University of Technology,Guangzhou 510641,China;Department of Applied Physics,The Hong Kong Polytechnic University,Hong Kong 999077,China;Graduate School of Advanced Science and Technology,Japan Advanced Institute of Science and Technology(JAIST),Nomi,Ishikawa 923–1292,Japan;Laboratory of Crystal Physics,Kirensky Institute of Physics,Federal Research Center KSC SB RAS,Krasnoyarsk 660036,Russia;Department of Engineering Physics and Radioelectronic,Siberian Federal University,Krasnoyarsk,660041,Russia;Research and Development Department,Kemerovo State University,Kemerovo 650000,Russia;Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education),School of Materials Science and Engineering,Shandong University,Jinan 250061,China;School of Physics and Optoelectronics,South China University of Technology,Guangzhou 510641,China)
基金
supported by the National Key Research and Development Program of China(2021YFE0105700)
the National Natural Science Foundations of China(51972118)
the Natural Science Foundation of Shandong Province(ZR2021ZD10 and ZR2018JL016)
Guangzhou Science&Technology Project(202007020005)
the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2017BT01X137)
funded by Russian Foundation for Basic Research(19-52-80003)。
