Ti/TiO_2包覆ZnO:Tb纳米纤维的光学性质

Optical properties of Ti/TiO_2 caped Tb^(3+)-doped ZnO nanofibers

用电纺丝方法制备了ZnO:Tb纳米纤维.用X-射线衍射、Raman光谱对其形貌做了表征.结果显示,ZnO:Tb纳米纤维为六方纤锌矿结构,Tb掺杂对ZnO的结晶性有影响.利用表面等离激元,通过对纳米纤维表面包覆金属Ti和TiO_2,比较了其光致发光谱,得到在325 nm激发下ZnO:Tb纳米纤维中稀土发光效率低的原因是ZnO和Tb之间不能进行有效的能量传递;包覆TiO_2后能提高稀土发光效率.

ZnO：Tb nanofibers are fabricated by electrospinning method. X-ray diffraction and Raman results show that the sample is of hexagonal phase. The positions of doped diffraction peaks shift toward the small angle and the shift does not change with Tb content. Photoluminescence （PL） spectra of Tb-doped ZnO nanofibers show a strong defect-related emission and indicate that the doping affects the crystallinity of ZnO. It is found that Ti-capped can enhance the ultraviolet emission of ZnO nanofiber, while the defect-related emission is depressed. The enhancement in ultraviolet emission is mostly attributed to the surface plasmon coupling effect at the interface. The PL results indicate that the ZnO is not a proper matrix for Tb^3＋ ion.