SrZn_2(PO_4)_2:Sn^(2+),Mn^(2+)荧光粉的发光性质及其能量传递机理

Photoluminescence properties and energy transfer of SrZn_2(PO_4)_2:Sn^(2+), Mn^(2+) phosphor

采用高温固相法制备了SrZn_2(PO_4)_2:Sn^(2+)(SZ_2P:Sn^(2+)),SrZn_2(PO_4)_2:Mn^(2+)(SZ_2P:Mn^(2+)),SrZn_2(PO_4)_2:Sn^(2+),Mn^(2+)(SZ_2P:Mn^(2+))荧光粉.通过X射线衍射、激发和发射光谱详细研究了荧光粉的物相和发光性质.在SrZn_2(PO_4)_2基质中,Sn^(2+)离子发射光谱是峰值位于461 nm宽带谱,归属于Sn^(2+)离子的3P1→1S0能级跃迁,SZ_2P:Mn^(2+)激发光谱由基质吸收带(200—300 nm)和位于352,373,419,431和466 nm的一系列激发峰组成,分别对应Mn^(2+)离子的~6A_41(~6S)→4E(4D),~6A_1(~6S)→4T2(D),6A1(~6S)→[~4A_1(~4G),~4E(~4G)],~6A_1(~6S)→~4T_2(~4G)和~6A_1(~6S)→~4T_1(~4G)能级跃迁,因此,SZ_2P:Sn^(2+)的发射光谱与SZ_2P:Mn^(2+)的激发光谱有较大范围的重叠.结果表明Sn^(2+)对Mn^(2+)发光有明显的敏化作用.基于Dexter电多极相互作用能量传递公式和Reisfeld近似原理分析,荧光粉SZ_2P:Sn^(2+),Mn^(2+)中Sn^(2+)-Mn^(2+)离子之间的能量传递机理属于电四极-电四极相互作用引起的共振能量传递,并计算出Sn^(2+)-Mn^(2+)离子之间能量传递临界距离Rc≈1.78 nm.通过改变Sn^(2+),Mn^(2+)离子掺杂浓度,实现了荧光粉发光颜色的调节,在254 nm短波紫外激发下荧光粉发出较强的蓝白光.研究结果表明SZ_2P:Sn^(2+),Mn^(2+)荧光粉有望应用于紧凑型节能灯照明领域,随着半导体紫外芯片技术的发展,有潜力应用于未来的白光发光二极管照明领域.

In this paper, SrZn2（PO4）2：Sn^2＋ （SZ2P：Sn^2＋）, SrZn2（PO4）2：Mn^2＋ （SZ2P：Mn^2＋）, SrZn2（PO4）2：Sn^2＋ ,and Mn^2＋ （SZ2P：Sn^2＋, Mn^2＋） phosphors are prepared by high temperature solid state reaction. The X-ray diffraction patterns and photoluminescence spectra of the phosphors are investigated in detail. The emission spectrum of SZ2P：Sn^2＋ is a wide band peaking at 461 nm due to 3P1 →4 1^S0 transition of Sn^2＋, and overlaps effectively with the excitation spectrum of SZ2P：Mn^2＋, which shows that the absorption of SrZn2（PO4）2 host, and a series of peaks at 352, 373, 419, 431, and 466 nm, corresponding to 6^A1 （6^S）→ 4^E（4^D）, 6^A1 （6^S）→4^T2（4^D）, →A1 （6^S）→[4^A1 （4^G）, 4→E（4→G）], 6^A1 （6^S）→ 4^T2（4^G） and 6^A1（6^S）→4^T1（4^G） transition, respectively, are assigned to a wide band ranging from 200 nm to 300 nm. Therefore, luminescence intensity of Mn^2＋ is enhanced significantly by co-doping Sn^2＋ in SrZn2（PO4）2 host. According to the Dexter＇s energy transfer formula of multipolar interaction and Reisfeld＇s approximation, it is demonstrated that the energy transfer between Sn^2＋ and Mn^2＋ is .due to the quadripole-quadripole interaction of the resonance transfer. The critical distance （Rc） of energy transfer is calculated to be about 1.78 nm. The tunable color is achieved by changing the doping concentrations of Sn^2＋ and Mn^2＋. The SZ2P：Sn^2＋, Mn^2＋ phosphor could emit strong blue-white light under the excitation of 254 nm ultraviolet （UV） light. The result shows that the SZ2P：Sn^2＋, Mn^2＋ is a promising phosphor for compact fluorescent lamp, and with the development of short wave UV semiconductor chip, this phosphor has potential applications in white light emitting diodes in the near future.