【作者】 蒋子江；

【导师】 黄宗浩；

【作者基本信息】 东北师范大学 ， 物理化学， 2009， 博士

【摘要】 半导体纳米材料由于其独特的光电特性受到人们的极大关注，其中纳米ZnO是当前应用前景较为广泛的高功能无机材料。由于ZnO是一种直接带隙的半导体材料，室温下能隙宽度为3.37 eV，激子束缚能高达60 meV，具有优良的物理和化学性质，其显著的表面效应、量子尺寸效应和宏观量子隧道效应，是目前光电子研究领域的热点。另一方面，由于聚对苯乙炔(PPV)以及聚芴的衍生物在同其它具有光电多功能特性的聚合物相比，自身有很多优点，一直作为共轭聚合物中具有光电多功能特性材料的典型代表而受到科技界的重视。因此，本文利用静电纺丝技术制备了共轭聚合物／ZnO纳米复合材料和其光伏器件，测试了复合材料的光电特性，发现了有意义的新现象，具体研究内容如下：(1)在总结了国内外制备纳米ZnO文献资料的基础上，结合下一步实验的需求，确立了以液相直接沉淀法为基础，制备ZnO纳米粒子的工艺。通过对影响ZnO粒子的多种因素的研究，总结出了制备纳米ZnO粒子的适宜工艺条件。产品经过XRD，TEM和TG-DTA表征，发现其晶型单一、完整，纯度高。纳米ZnO粒子大部分呈球形，粒径大小分布均匀，分散性良好平均粒径为25nm。(2)在成功制备纳米级氧化锌粒子的基础上，首次报导了通过原位和共混的方法利用静电纺丝技术合成了共轭聚合物PPV中含有ZnO纳米粒子的纳米纤维。这些复合纳米纤维通过荧光显微镜、原子力显微镜、场发射扫描电镜、荧光光谱、傅里叶红外光谱和X射线粉末衍射仪来表征。在ZnO纳米粒子／PPV复合纳米纤维中，ZnO纳米粒子分散均匀且不团聚。另外，ZnO纳米粒子掺入共轭聚合物PPV中增强了PPV纳米纤维的发光量子效应。ZnO纳米粒子／PPV复合纳米纤维的能带结构有利于PPV的激子产生和辐射。这些具有优秀的荧光性能的复合纳米纤维在许多领域有着潜在的应用。(3)在发现ZnO纳米粒子掺入共轭聚合物PPV中增强了PPV纳米纤维的发光量子效应后，为了更深入研究其薄膜对光伏器件的影响，我们将ZnO纳米晶引入到一种新型的聚芴衍生物：poly(2，7-(9，9-dioctyl-fluorene)-alt-5，5-(4’，7’-di-2-thienyl-2’，1’，3’，-benzothiadiazole)(PFDTBT)。该单层膜的光伏器件具有非常有意义的光伏效应(具备最佳性能的是含有60 wt％ZnO的器件)：光电流密度是：1.17 mA／cm~2，开路电压是：0.81 V，填充因子是：0.09，电源转换效率是：0.009％。这个聚芴衍生物是非常出色的荧光和光伏材料。利用现代分析测试手段：场发射扫描电子显微镜(FE-SEM)、透射电子显微镜(TEM)、荧光光谱(PL)等，对由一维共轭聚合物／ZnO复合纳米纤维和薄膜进行表征。探究了其发光和表面光生电荷行为、发光效率、纤维复合结构对发光强度的影响。此项研究不仅丰富了无机半导体纳米粒子的制备方法，而且为设计合成一维结构的聚合物／无机物复合纳米材料提供了实践上的依据，从而加快了聚合物纳米材料的实用化进程。更多还原

【Abstract】 Semiconductor nanocrystals have attracted much interest due to their electricaland optical properties. Nanoscale Zinc oxide(ZnO) is currently of potentialapplications as a functional inorganic material. Since it has many special mechanical,optical, electrical, magnetic, calorifics and chemical properties which differ from thecorresponding bulk materials due to its size effect, surface effect and quantum effect,as a wide band gap semiconductor material with large exiton binding energy of 60meV at room temperature, it is attractive for many new applications in industry andhigh-tech fields.In this thesis, electrospinning technique and photovoltaic device technique wereapplied to prepare polymer-ZnO nano-composite materials, and then the controllableUV luminescence of ZnO was performed. The details are as following:(1) On bases of the preparations of ZnO nanoparticles in references, a process ofdirect precipitation approach was established to synthesize ZnO nanoparticles and theeffects of various factors have been investigated. The appropriate process isconcluded. The product was characterized by XRD, TEM and TG-DTA, and theresults show that the product is single crystal type and of high purity. Most of theparticles are ball-shaped and are uniformly-distributed in diameter. The dispersibilityis excellent and the average particle size is less than 25nm.(2) Based on the synthesis of the ZnO nano particles, we report for the first timeon the synthesis of ZnO nanoparticles in conjugated polymer(PPV) nanofibers byelectrospinning and the coupling of the in situ and blend methods. These compositenanofibers were characterized by fluorescence microscopy, atomic force microscope(AFM), field emission scanning electron microscopy(FE-SEM), transmissionelectron microscopy(TEM), photoluminescence(PL) spectra, Fourier transforminfrared(FT-IR) spectroscopy, and X-ray powder diffraction(XRD). In ZnOnanoparticles/PPV composite nanofibers, ZnO nanoparticles were distributed uniformly without aggregation. In addition, the incorporation of ZnO nanoparticlesinto the conjugated polymer PPV strengthened the photoluminescence(PL) quantumefficiency of the PPV nanofibers. The band structure of the ZnO nanoparticles/PPVcomposite nanofibers should be in favor of photoexciton generation and radiation ofPPV. These composite nanofibers with excellent fluorescent property are potentiallyinteresting for many applications.(3) Since that the incorporation of ZnO nanoparticles into the conjugatedpolymer PPV strengthened the photoluminescence(PL) quantum efficiency of thePPV nanofibers, the ZnO nanoparticles which show perfect crystal character of thewurtzite ZnO were introduced into a new kind of polyfluorene copolymers, poly(2, 7-(9, 9-dioctyl-fluorene)-alt-5, 5-(4’, 7’-di-2-thienyl-2’, 1’, 3’,-benzothiadiazole)(PFDTBT),for more in-depth study of its thin film on the impact of photovoltaic devices wereprepared. This single-layer photovoltaic device performs a significant photovoltaicresponse(the best performed device is that containing 60 wt% of ZnO): photocurrentdensity of 1.17 mA/cm~2, open-circuit voltage of 0.81 V, fill factor of 0.09, andpower-conversion efficiency of 0.009%, which shows that polyfluorene derivative isexcellent fluorescence and photovoltaic material.One dimensional structure made from conjugated polymer/ZnO compositenanofibers were characterized by modern analysis and testing means(SEM, TEM, PL,etc.). The luminescence, surface photoelectric charge action, luminescence efficiencyand the effect of composite structure of nanofibers on the luminescent intensity wereinvestigated. These investigations not only enriched the synthesis methods forinorganic nanoparticles, but also provided a practical gist for synthesizing 1Dpolymer/inorganic composite nanomaterials. Consequently, practicality course ofpolymer nanomaterials were quicken.更多还原