NaGd(WO4)2:Yb3+/Tm3+反蛋白石光子晶体的制备与上转换发光调制研究

三维光子晶体具有长程有序的结构特点, 在可见和近红外光谱范围内有着广泛的应用。光子晶体的一个重要性质是其对嵌入其中的发光中心自发辐射具有调制作用。本研究利用自组装和模板辅助法制备高质量的三维NaGd(WO₄)₂:Yb³⁺/Tm³⁺反蛋白石光子晶体, 探究了光子带隙对Tm³⁺离子上转换荧光发射与发光动力学的调制作用。通过对比分析发现, 由于反蛋白石光子晶体独特的周期性大孔结构和光子带隙效应, 处于光子带隙内的Tm³⁺离子¹G₄-³H₆的发光强度被抑制约45%, 自发辐射速率(SDR)被抑制约30%, 同时上转换局域热效应得到有效的调制。本实验结果对探索新型高效稀土掺杂上转换发光材料和提高上转换发光效率有指导意义。

Preparation and Modified Upconversion Luminescence In NaGd(WO4)2:Yb3+/Tm3+ Inverse Opal Photonic Crystals

Photonic crystal (PC) possesses long-scale periodicity and has been widely applied in modifying visible and near-infrared photonic band gap. One of the extraordinary properties of the PCs is the modulation on spontaneous emission of embedded luminescence centers. In this study, three-dimensional NaGd (WO₄)₂:Yb³⁺/Tm³⁺ inverse opal photonic crystals (IOPC) with highly oridered periodic structure were prepared by self-assembly method using PMMA as template. The modulation effect of PC on emission spectra and dynamics of Tm³⁺ ions were systemically studied. In NaGd (WO₄)₂:Yb³⁺/Tm³⁺ inverse opal photonic crystals, due to unique cavity structure and photonic band gap effect, the emission line of ¹G₄-³H₆ transition decreases by ~45% and the spontaneous radiation rate is suppressed by ~30%. Meanwhile, the up-conversion local thermal effect is largely suppressed. This experimental analysis indicates that the IOPC structure is an effective device for improving efficiency of up-conversion luminescence.