静电纺丝纳米ZrO_2:Ti纤维的制备与发光性质的研究

Synthesis and Optical Property Studies of Long-Lasting Phosphor ZrO_2:Ti Electrospinning Fibers

通过静电纺丝和高温煅烧相结合的方法制备了一维钛掺杂氧化锆的纳米纤维。复合纤维在1 000℃煅烧后,由于模板剂、聚乙烯吡咯烷酮(PVP)在高温下的分解,纤维直径大大减小,扫描电镜观察最终得到直径100 nm左右的单斜相纤维。利用稳态光谱和时间分辨光谱技术室温下研究了纤维的光致发光性质。结果表明发射主峰在467 nm的宽带,在350 nm处有一个小肩峰。两种不同的发光行为可以通过ZrO2∶Ti纳米纤维中存在的两种情况的氧空穴作为电子俘获中心来解释。一种由电荷补偿产生的氧空位,俘获电子,产生467 nm处Ti参与的发光现象。另外一种ZrO2表面缺陷导致的氧空穴,对应于350 nm的发光现象,没有发现长余辉现象。测得的激发态寿命短于体材料而长于普通的纳米晶,可能是由于一维纳米结构的独特性质导致的。

One-dimensional （1D） nanostructures, such as nanorods, nanofibers and nanotubes, have been an active subject of intense research due to the unique transport properties, quantum effects and potential applications in electronics and photonics. One-dimensional Ti doped ZrO2 nanofibers with interesting long-lasting phosphorescence were successfully prepared by electrospinning from properly selected Ti, Zr and polymer precursors and subsequent calcination treatment. The as obtained ZrO2 ： Ti ultralong nanofibers are monoclinic phase with average diameter of ca. 100 nm observed by scanning electron microscope （SEM）. The sample obtained after calcinations at 1 000℃ shows much decrease in size due to the decomposition and removal of the PVP component that played the role of template for the fiber formation during electrospinning process, Photoluminescence properties of the ZrO2 ： Ti fibers were studied by means of steady state and time resolved photoluminescence spectroscopy and discussed in detail. Room-temperature photoluminescence measurement shows a prominent peak at 467 nm （2. 65 eV） with a weak shoulder band around 350 nm （3.54 eV）. Different emission behavior may be due to the existence of two kinds of oxygen vacancies. Two Ti^3＋ ions substituting a Zr^4＋ ion produce one oxygen vacancy for charge compensation, which are effective and deep traps for excited electrons in the conduction band under irradiation. The weak emission band at 350 nm is attributed to the oxygen vacancy caused by surface defects trapping electrons. Longer excited state lifetime than the common ZrO2 ： Ti nanocrystals was observed and may be ascribed to the unique characteristic of one-dimensional （1D） nanostructures.