采用均相沉淀法制备了Y(OH)3微米颗粒,经1 100 ℃焙烧后制备出具有上转换发光性质的Yb3+- Tm3+-Gd3+共掺的Y2O3微米晶体,讨论了Yb3+ -Tm3+ -Gd3+在Y2O3中能量传递过程及壳层对发光强度的影响。980 nm近红外光激发下的上转换光谱表明,在Yb3+-Tm3+-Gd3+共掺Y2O3体系中,核-壳结构大幅提高了Gd3+离子和Tm3+离子的上转换发光强度,尤其是样品在紫外发光部分的增强相比于可见和红外光部分更为明显。同时,通过研究Tm3+和Gd3+在不同波段的发光强度与泵浦功率的关系探讨了氧化物中上转换发光的机制。

Y2O3∶Yb/Tm/Gd@Y2O3 microcrystals with core-shell structure were prepared by homogeneous precipitation method and then annealed at high temperature. The microparticles were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and luminescent spectra. Upconversion spectra and excitation power dependence indicate that the energy transfer from Tm3+ to Gd3+ plays a crucial role in populating the excited states of Gd3+. The shortest wavelength of upconversion emissions in Y2O3 matrix is converted from the infrared region. Meanwhile, the core-shell structure greatly improved the upconversion fluorescence intensity of Gd3+ in Yb3+-Tm3+-Gd3+ codoped system.