以乙二醇为溶剂, 采用低温溶剂热法制备了Ho3+/Yb3+共掺杂In2O3纳米晶。利用X射线晶体衍射(XRD)、透射电子显微镜(TEM)对粒子的结构和形貌进行表征, 结果表明, 合成的样品为纯的立方相In2O3, 颗粒尺寸约为30 nm。通过上转换发光(UCL)光谱研究了粒子的上转换发光性质, 在980 nm半导体激光激发下, In2O3∶Ho3+,Yb3+纳米晶发射出强的绿色和弱的红色上转换发光, 分别归属于Ho3+离子(5F4,5S2)→5I8和5F5→5I8跃迁。研究了不同Ho3+和Yb3+离子掺杂浓度对上转换发光性能的影响, 确定了Ho3+和Yb3+最佳掺杂摩尔分数分别为3%和4%。双对数曲线显示,绿光和红光的发射过程均为双光子吸收过程。对样品的上转换发光机制进行了初步讨论。

In2O3∶Ho3+,Yb3+ nanocrystals with efficient upconversion luminescence were prepared by solvent thermal method using glycol as solvent. The samples were characterized by X-ray diffraction(XRD), transmission electron microscopy (TEM), diffuse reflectance spectra, and upconversion luminescence spectra. XRD results indicate that the products are cubic phase. TEM images show that the In2O3∶Ho3+,Yb3+ nanoparticles are sphere shape with an average size of 30 nm. The diffuse reflectance spectra give four narrow bands at 448, 538, 644 and 975 nm, corresponding to the 5I8→5G6 (448 nm), 5I8→5S2/5F4 (538 nm), 5I8→5F5 (644 nm) transitions of Ho3+ ions and 2F7/2→2F5/2 (975 nm) transition of Yb3+ ions. Under the excitation of 980 nm, In2O3∶Ho3+,Yb3+ nanocrystals can emit strong green emission and weak red emission, corresponding to (5F4,5S2)→5I8, 5F5→5I8 transitions of Ho3+. Upconversion luminescence of In2O3∶Ho3+,Yb3+ nanocrystals codoped with different concentrations of Ho3+ and Yb3+ ions were investigated to improve the luminescene intensity. The results show that the strongest upconversion emission can be achieved at a Ho3+ mole fraction of 3% and an Yb3+ mole fraction of 4%. The lnI-lnP curves show that both the green and red emissions are double-photon process and the possible mechanism is proposed.