表面活性剂组装的Y_2O_3∶Eu纳米管及其位置选择光谱

Fabrication and Site Selective Spectroscopy of Y_2O_3∶Eu Nanotubes

利用表面活性剂为模板,通过自组装制备出了具有管状结构的Y2O3∶Eu纳米材料。透射电子显微镜证实了管状结构的形成。在紫外光的激发下,Y2O3∶Eu纳米管表现出与纳米颗粒不同的发光性质。由电荷迁移带和低温下的激光选择激发光谱可以推测,处于纳米管壁内部的发光中心具有较为确定的格位对称性,其发射光谱具有清晰的光谱结构。由于表面缺陷的存在,纳米管壁近表面的Eu3+离子处于较为复杂的微环境中,其发射光谱表现为非均匀展宽的光谱线形。

Y_2O_3∶Eu nanotubes were synthesized by a surfactant assembly mechanism. Under an ultraviolet-light excitation, the nanotubes present luminescence properties different from that of Y_2O_3∶Eu nanoparticles. The peak position of the charge transfer band in excitation spectra varies with the monitoring emission peaks, while the emission spectra are dependent on the excitation wavelength. Laser selective spectroscopy was performed to distinguish the local symmetries of the Eu^(3+) ions in the nanotubes. The results of laser-selective excitation indicate that the emission centers near the surface of nanotube walls exhibit inhomogeneously broadened spectra without spectral structures while the two sites (site B and site C) inside the nanotube walls present legible spectral structures. It is concluded by the number and peak positions of the spectral lines that the sites B and C possess different site symmetries.