SrZn2(PO4)2:Sn2+,Mn2+荧光粉的发光性质及其能量传递机理

采用高温固相法制备了SrZn₂(PO₄)₂:Sn²⁺(SZ₂P:Sn²⁺), SrZn₂(PO₄)₂:Mn²⁺(SZ₂P:Mn²⁺), SrZn₂ (PO₄)₂:Sn²⁺, Mn²⁺(SZ₂P:Sn²⁺, Mn²⁺) 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SrZn₂(PO₄)₂ 基质中, Sn²⁺离子发射光谱是峰值位于461 nm宽带谱, 归属于Sn²⁺离子的³P₁→¹S₀能级跃迁, SZ₂P:Mn²⁺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Mn²⁺离子的⁶A₁(⁶S)→⁴E(⁴D), ⁶A₁(⁶S)→⁴T₂(⁴D), ⁶A₁(⁶S)→⁴A₁(⁴G), ⁴E(⁴G)], ⁶A₁(⁶S)→⁴T₂(⁴G)和⁶A₁(⁶S)→⁴T₁(⁴G)能级跃迁, 因此, SZ₂P:Sn²⁺ 的发射光谱与SZ₂P:Mn²⁺的激发光谱有较大范围的重叠. 结果表明Sn²⁺对Mn²⁺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SZ₂P:Sn²⁺, Mn²⁺中Sn²⁺-Mn²⁺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Sn²⁺-Mn²⁺离子之间能量传递临界距离R_c ≈ 1.78 nm. 通过改变Sn²⁺, Mn²⁺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SZ₂P:Sn²⁺, Mn²⁺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.

Photoluminescence properties and energy transfer of SrZn2(PO4)2:Sn2+, Mn2+ phosphor

In this paper, SrZn₂(PO₄)₂:Sn²⁺ (SZ₂P:Sn²⁺), SrZn₂(PO₄)₂:Mn²⁺ (SZ₂P:Mn²⁺), SrZn₂(PO₄)₂:Sn²⁺, and Mn²⁺ (SZ₂P:Sn²⁺, Mn²⁺) 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:Sn²⁺ is a wide band peaking at 461 nm due to ³P₁ →¹S₀ transition of Sn²⁺, and overlaps effectively with the excitation spectrum of SZ₂P:Mn²⁺, 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 ⁶A₁(⁶S)→⁴E(⁴D), ⁶A₁(⁶S)→⁴T₂(⁴D), ⁶A₁(⁶S)→⁴A₁(⁴G), ⁴E(⁴G)], ⁶A₁(⁶S)→⁴T₂(⁴G) and ⁶A₁(⁶S) →⁴T₁(⁴G) transition, respectively, are assigned to a wide band ranging from 200 nm to 300 nm. Therefore, luminescence intensity of Mn²⁺ is enhanced significantly by co-doping Sn²⁺ 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 Sn²⁺ and Mn²⁺ is due to the quadripole-quadripole interaction of the resonance transfer. The critical distance (R_c) of energy transfer is calculated to be about 1.78 nm. The tunable color is achieved by changing the doping concentrations of Sn²⁺ and Mn²⁺. The SZ₂P:Sn²⁺, Mn²⁺ phosphor could emit strong blue-white light under the excitation of 254 nm ultraviolet (UV) light. The result shows that the SZ₂P:Sn²⁺, Mn²⁺ 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.