【作者】 胡鹏；

【导师】 余海湖；

【作者基本信息】 武汉理工大学 ， 光电子及信息材料， 2008， 博士

【摘要】 硫化镉(CdS)是典型的Ⅱ-Ⅵ族化合物,是一种宽禁带直接半导体,在太阳能转换、非线性光学、光化学电池和光催化方面具有广泛用途。硫化铅(PbS)是一种重要的半导体材料,其能带间隙为0.41 eV,具有较大的激子波尔半径(18nm),在非线性光学器件、红外探测器、显示装置、发光二极管以及太阳能光伏特电池方面有很好的应用前景。因此CdS、PbS纳米材料的研究具有重要意义。分别采用模板法、超声化学法、表面活性剂辅助化学合成法合成了CdS、PbS、CdS/PbS纳米复合材料,利用X射线衍射(XRD)、透射电镜(TEM)、吸收光谱和荧光光谱(PL)等测试手段对纳米材料进行了分析。采用前驱物模板-界面反应法,分别合成了CdS纳米空心球-管状结构、PbS纳米空心球、CdS/PbS纳米复合材料。CdS纳米空心球-管状结构的XRD显示,CdS属六面晶系;TEM图片结果表明,CdS纳米结构为空心管状结构;吸收光谱显示,CdS在407 nm处有较明显的激子吸收峰;荧光光谱显示,CdS在470 nm处出现荧光发射峰。PbS纳米空心球属面心立方晶系;在1906 nm处出现激子吸收峰;在1328 nm和1516 nm处出现两个荧光发射峰。CdS/PbS纳米复合材料中的CdS和PbS分别属六面晶系和面心立方晶系;在432 nm、1682 nm、1735 nm处分别出现CdS和PbS的吸收峰;在472 nm、495 nm、1610 nm处分别出现CdS和PbS的荧光发射峰。采用超声化学法,分别合成了CdS纳米立方体、PbS纳米立方体和CdS/PbS复合纳米粒子。CdS纳米立方体的XRD图谱显示,CdS属六面晶系;TEM结果表明,CdS纳米结构为立方体结构,边长为10～15 nm;吸收光谱显示,CdS在409 nm处有较明显的激子吸收峰;荧光光谱显示,CdS在525 nm处出现荧光发射峰。PbS纳米立方体属面心立方晶系;边长为40～60 nm;在1728 nm处出现激子吸收峰;在1641 nm处出现荧光发射峰。CdS/PbS复合纳米粒子中的CdS和PbS分别属六面晶系和面心立方晶系;在429 nm、1411 nm、1908 nm处分别出现CdS和PbS的吸收峰;在515 nm、546 nm、1728 nm、1738 nm处分别出现CdS和PbS的荧光发射峰。采用阴离子表面活性剂二-(2-乙基己基)琥珀酸酯磺酸钠(AOT)、六偏磷酸钠作为稳定剂,分别合成了两种CdS纳米粒子。AOT稳定的CdS纳米粒子的XRD图谱显示,CdS属六面晶系;TEM图片结果表明,其平均粒径为5～8 nm;吸收光谱显示,在516 nm处有激子吸收峰;荧光光谱显示,CdS纳米粒子在516nm处出现荧光发射峰。六偏磷酸钠稳定的CdS纳米粒子属六面晶系;其平均粒径为2～3 nm;在303 nm处有激子吸收峰;在336 nm处出现荧光发射峰。采用表面活性剂聚乙烯吡咯烷酮(PVP)作为稳定剂,合成了PbS纳米棒。XRD图谱显示,PbS属面心立方晶系。TEM图片结果表明,直径约为500nm,长约为11μm的PbS纳米棒。吸收光谱显示,在1731 nm处有激子吸收峰。荧光光谱显示,在1516 nm处出现荧光发射峰。采用阴离子表面活性剂硫代乙醇酸作为稳定剂,分别合成了PbS量子点和CdS/PbS杂化量子点。TEM图片结果表明,PbS量子点的平均粒径只有1～2 nm;而CdS/PbS杂化量子点的平均粒径则为2～3 nm。将所制得的六偏磷酸钠稳定的CdS纳米粒子、硫代乙醇酸稳定的PbS量子点、硫代乙醇酸稳定的CdS/PbS杂化量子点分别与阿利新蓝(AB)在ITO导电玻璃上进行交替静电自组装,制得纳米粒子/AB薄膜,并将其制成光电池。线性伏安曲线表明,上述光电池在光照条件下,可以产生瞬时电流,分别比没有光照条件下大1.5倍、5倍和2倍左右,其中PbS量子点/AB薄膜光电池在红外区有较明显的光电效应。更多还原

【Abstract】 Cadmium sulfide（CdS）,an intrinsic semiconductor inⅡ-Ⅵgroup with a direct transition band structure,is widely used in the field of solar energy conversion, nonlinear optics,actinochemistry battery and photo catalysis.Lead sulfide（PbS）is an important semiconductor material with a small bandgap（0.41 eV）and large exciton Bohr radius（18 nm）.It is promising in the applications in the fields of nonlinear optics,IR detectors,displaying devices,light emitting diode and solar cell.Thus,it is of interest to carry out studies on PbS and CdS nanomaterials.Template method,sonochemistry method,surfactant assisted chemical synthesis method were used to prepare CdS,PbS and CdS/PbS composite materials.Some test methods such as XRD,TEM,absorption spectra and PL were used to analyze these nanoparticles.CdS hollow sphere-tubular nano-structures,PbS hollow sphere nano-structures and CdS/PbS composite nano-materials were prepared via the source template-interface reaction route.The result of XRD analysis showed that the crystal structures of CdS were hexagonal;the result of TEM observation showed that the CdS samples were hollow sphere-tubular nanostructures;the result of optical absorbance measurement presented that exciton absorption peak of CdS appear at 407 nm;the result of PL measurement showed that fluorescence emission peak of CdS appeared at 470 nm.The crystal structures of PbS were face-centered cubic,the PbS samples were nano-hollow spheres,with exciton absorption peak at 1906 nm and fluorescence emission peaks at 1328 nm and 1516 nm.CdS and PbS of the CdS/PbS composite nano-materials were separately of the structures of hexagonal and face-centered cubic,with exciton absorption peaks at 432 nm,1692 nm and 1735 nm and fluorescence emission peaks at 472 nm,495 nm and 1610 nm.Nano-cubic CdS,PbS,and CdS/PbS composite nanoparticles were prepared via sonochemistry method.The result of XRD analysis showed that the crystal structure of CdS was hexagonal;the result of TEM observation showed that cubic structure; the result of optical absorbance measurement presented that exciton absorption peak of CdS appeared at 409 nm;the result of PL measurement showed that fluorescence emission peak of CdS appeared at 525 nm.The crystal structure of PbS was face-centered cubic,with exciton absorption peak at 1728 nm,fluorescence emission peak of PbS appeared at 1641 nm.CdS and PbS of the CdS/PbS composite nano-materials were separately of the structures of hexagonal and face-centered cubic, with exciton absorption peaks at 429 nm,1411 nm and 1908 nm and fluorescence emission peaks at 515 nm,546 nm,1728 nm and 1738 nm. CdS nanoparticles were prepared adding anionic surfactant AOT,Na（PO₃）₆ as stabilizer respectively.The result of XRD analysis showed that the crystal structure of CdS was hexagonal.The result of TEM observation showed that the average particle size of CdS nanoparticles was 5～8 nm;the result of optical absorbance measurement presents that exciton absorption peak of CdS nanoparticles appeared at 401 nm;the result of PL measurement showed that fluorescence emission peak of CdS nanoparticles appear at 516 nm.The average particle size of CdS stabilized with Na（PO₃）₆ was 2～3 nm,with exciton absorption peak at 303 nm and fluorescence emission peak at 336 nm.PbS nano-rods were prepared by using surfactant PVP as stabilizer.The result of XRD analysis showed that the crystal structure of PbS was face-centered cubic.The result of TEM observation showed that the diameter and the length of the PbS nanorods was about 500 nm and up to 11μm.The result of optical absorbance measurement presented that exciton absorption peak of PbS appeared at 1731 nm. The result of PL measurement showed that fluorescence emission peak of PbS appeared at 1516 nm.PbS quantum dots,CdS/PbS hybrid quantum dots were prepared by using anionic surfactant thioglycollate as stabilizer.The result of TEM observation showed that the average particle size of PbS quantum dots was only 1～2 nm;the average particle size of CdS/PbS hybrid quantum dots was only 2～3 nm.Through alternate static electric self-assembly method,nanoparticle/Alician Blue 8GX（AB）thin films were plated on ITO conductive glass,then assembled photocell. The linear voltammetry curve presented the instantaneous current efficiency of the photocell with light are about 1.5 times,5 times,2 times higher than that without light. Among them,the PbS quantum dots stabilized with thioglycollate/AB thin films photocell was more significant photoelectric effect in the infrared spectral region.更多还原