Liu Lihong, Wang Le, Zhang Chenning, Cho Yujin, Dierre Benjamin, Hirosaki Naoto, Sekiguchi Takashi, Xie Rong-Jun
†College of Optics and Electronic Science and Technology, China Jiliang University, Hangzhou 310018, China.
§Fine Particles Engineering Group, Materials Processing Unit, National Institute for Materials Science, Tsukuba, Ibaraki 305-0047, Japan.
Inorg Chem. 2015 Jun 1;54(11):5556-65. doi: 10.1021/acs.inorgchem.5b00683. Epub 2015 May 20.
A series of Eu(2+)- and Mn(2+)-codoped γ-AlON (Al1.7O2.1N0.3) phosphors was synthesized at 1800 °C under 0.5 MPa N2 by using the gas-pressure sintering method (GPS). Eu(2+) and Mn(2+) ions were proved to enter into γ-AlON host lattice by means of XRD, CL, and EDS measurements. Under 365 nm excitation, two emission peaks located at 472 and 517 nm, resulting from 4f(6)5d(1) → 4f(7) and (4)T1(4G) → (6)A1 electron transitions of Eu(2+) and Mn(2+), respectively, can be observed. Energy transfer from Eu(2+) to Mn(2+) was evidenced by directly observing appreciable overlap between the excitation spectrum of Mn(2+) and the emission spectrum of Eu(2+) as well as by the decreased decay time of Eu(2+) with increasing Mn(2+) concentration. The critical energy-transfer distance between Eu(2+) and Mn(2+) and the energy-transfer efficiency were also calculated. The mechanism of energy transfer was identified as a resonant type via a dipole-dipole mechanism. The external quantum efficiency was increased 7 times (from 7% for γ-AlON:Mn(2+) to 49% for γ-AlON:Mn(2+),Eu(2+) under 365 nm excitation), and color-tunable emissions from blue-green to green-yellow were also realized with the Eu(2+) → Mn(2+) energy transfer in γ-AlON.
采用气压烧结法（GPS）在1800℃、0.5MPa氮气气氛下合成了一系列Eu(2+)和Mn(2+)共掺杂的γ-AlON（Al1.7O2.1N0.3）荧光粉。通过XRD、CL和EDS测量证明Eu(2+)和Mn(2+)离子进入了γ-AlON主晶格。在365nm激发下，可以观察到位于472和517nm处的两个发射峰，分别由Eu(2+)和Mn(2+)的4f(6)5d(1)→4f(7)和(4)T1(4G)→(6)A1电子跃迁产生。通过直接观察Mn(2+)的激发光谱与Eu(2+)的发射光谱之间明显的重叠以及随着Mn(2+)浓度增加Eu(2+)的衰减时间缩短，证明了从Eu(2+)到Mn(2+)的能量转移。还计算了Eu(2+)和Mn(2+)之间的临界能量转移距离和能量转移效率。能量转移机制被确定为通过偶极-偶极机制的共振类型。在365nm激发下，外部量子效率提高了7倍（从γ-AlON:Mn(2+)的7%提高到γ-AlON:Mn(2+),Eu(2+)的49%），并且通过γ-AlON中Eu(2+)→Mn(2+)的能量转移还实现了从蓝绿色到绿黄色的颜色可调发射。
