水热法合成Zn1-xCoxS纳米棒的光学性能研究

Optical properties of Zn1-xCoxS nanorods synthesized by hydrothermal method

摘要:

以乙二胺为修饰剂,采用水热法合成了不同掺杂浓度的Zn_1-xCo_xS (x=0、0.01、0.03、0.05和0.07) 纳米棒,并通过X射线衍射(XRD)、场发射扫描电子显微镜(FESEM)、高分辨透射电子显微镜(HRTEM)、X射线能量色散分析谱仪(XEDS)、紫外可见吸收光谱(UV-vis)、光致发光光谱(PL) 和傅里叶红外光谱(FT-IR)对样品的晶体结构、形貌和光学性能进行表征。实验结果表明,所有样品具有结晶良好的六方纤锌矿结构, 样品中掺杂的Co₂₊以替代Zn₂₊的形式进入到ZnS 晶格中。形貌为一维的纳米棒状结构,分散性良好。随着Co掺杂量的增加,晶胞体积逐渐减小,晶粒尺寸增大,晶格常数发生收缩。UV-vis光谱发现掺杂样品的光学带隙发生了红移现象。PL谱图表明样品存在紫光(402nm)、蓝光(470nm)、黄光(600nm)和红外(826nm)四个明显的发光峰,随着Co掺杂浓度的增加,发光强度呈现减小趋势。红外光谱的吸收峰位并没有随着掺杂浓度的增加而发生变化。

Abstract:

Co doped Zn_1-xCo_xS nanorods with different concentration ratio (x=0, 0.01, 0.03, 0.05 and 0.07) were successfully synthesized by hydrothermal method using ethylenediamine as a modifier. The crystal microstructure, morphology and optical properties of the samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), X-ray energy dispersive spectrometry (XEDS), Ultraviolet–visible Diffuse Reflectance spectroscopy (UV–vis DRS), photoluminescence spectra (PL) and Fourier transform Infrared spectroscopy (FTIR). The experiment results show that all samples synthesized by this method possess wurtzite structure with good crystallization, which indicates that all Co₂₊ successfully substituted for the lattice site of Zn₂₊ and generate single-phase Zn_1-xCo_xS. The morphology is one-dimensional rod-like shape with good dispersion. The the grain size increases, the cell volume decreases and the lattice constant occurs shrink with the increase of Co content. UV–vis spectra reveals the band gap of doped Zn_1-xCo_xS nanorods occurs red shift compare to that of the pure ZnS. PL spectra shows that the samples have obvious violet (402nm), blue (470nm, yellow (600nm) and infrared (826nm) emission peaks, the luminescence intensity decreases with the increase of the Co doping concentration.The FTIR spectrum shows that the absorption peak position does not change with the increase of the Co doping concentration.