【作者】 李子亨；

【导师】 王德军；

【作者基本信息】 吉林大学 ， 物理化学， 2005， 博士

【摘要】 本文在表面光电压谱和场诱导表面光电压谱技术基础上建立了光伏场扫描技术。并用它来证明所提出的电场诱导偶极模型。进一步发展了表面光伏理论,使它在解释纳米半导体颗粒和纳米半导体复合物的光伏中更具普遍性和适用性。指出外电场诱导产生的纳米粒子内部偶极自建场是光生电荷迁移的原动力。针对太阳能转换、光催化作用和分子电子学器件等领域所共同关心的问题,研究了系列卟啉/TiO2异质结的表面光伏行为。发现卟啉取代基的种类、个数和空间位阻效应都对光伏行为有显著的影响。纳米TiO2粒径也是影响光伏行为的主要因素。场诱导偶极模型对卟啉/TiO2体系也适用。光伏场扫描技术能够被成功用于有效评价有机-无机异质结之间的作用。更多还原

【Abstract】 The behavior of surface photogenerated charge transfer in organic/inorganic heterojunction is the basic behavior in photo-electric conversion, photocatalysis and molecular-electric device. Surface Photovoltage Spectra (SPS) is a sensitive tool for detecting the photogenerated charge at the surface of semiconductor materials, which makes it the most important measuremant for studying the behavior of photognerated charge transfer at the surface and interface of semiconductor materials. Applied external electric field can promote the separation of photogenerated electron-hole pairs, thus influence the transfer, capture and recombination of photogenerated carriers. So, field induced surface photovoltage spectra (FISPS) based on the basic of field effect which is normally considered as the steady state SPS can detect the nice change of photogenerated charge at the surface of semiconductor materials. In this thesis, we built the photovoltage electric field scanning (PVEFS) technique based on the SPS and FISPS. This measurement focuses on the photogenerated charge transfer, capture and recombination on the semiconductor materials. Therefore, we developed the basic theory of surface photovoltage and introduced the electric field induced dipole model for the first time. We also built the method for interpretting nanoparticles and nano-cmoplexs which is significantly useful for comprehending the behavior of photogenerated chrage transfer. I. We pointed out that the semiconducor nanoparticles anisomerously bind up the photogenerated charge and determined the state of free exction and bound exction after the resrarch on the TiO2 nanoparticles in chapter II. We have also discussed the photovoltaic characteristic at the interface of anatase and rutile, and introduced the conception of the photovoltage reverse. Based on the determination of free exction and bound exction, we introduced the electric field induced dipole model and pointed out that the built-in field is the significantly driving force which affects the photovoltage. Based on the comprehension of chapter II, we have disscussed the factors such as conductivity, particle size and absorbed substance which make the traditional theory of photovoltage including the solid energy band theory is not suitable for interpretting the behavior of photogenerated charge transfer in nano semiconductor materials in chapter V. Based on the field induced dipole mechanism, we built the photovoltage electric field scanning (PVEFS) technique. Through the analysis of obtained curves, we found that it almost suits all of our smaple. II. Chapter III and IV is mainly focus on studying the porphyrin/TiO2 and liquid crystal/TiO2 system. We have studied the photovoltaic properties of porphyrin/TiO2 system in chapter III. We found some factors that affect the photovoltage of porphyrin: 1. The size of TiO2, 2. Category of functional group of porphyrin. 3. The amount of functional group of porphyrin. The conclusion is as follows: 1. The TiO2 with small size facilitate the separation of photogenerated electron-hole pairs. 2. The category of the functional group of porphyrin significantly affect the photovoltage of system, the electron donating group makes porphyrin easily contact with TiO2, while the electron withdraw group makes this difficulty. 3. The amount of functional group also affect the generation of photovoltage. At the same time, the testing results in chapter III are also useful for introducing the dipole theory in chapter V. Chapter IV studied the photovoltage characteristic of liquid crystal/TiO2 system. The results show that photovoltage correlates not only with the mentioned factors in chapter III, but also with the steric hindrance effect. Porphyrin with evident更多还原