【作者】 张智；

【导师】 张复实；

【作者基本信息】 清华大学 ， 化学， 2005， 硕士

【摘要】 电子的转移和传输特性是判断光电转换体系性能的关键因素,在有机光电功能体系中,这一特性取决于所选择的不同分子工作物质之间的相互关系,而这种相互关系则是由工作物质的分子结构决定的。本文选取有机太阳能电池研究中常用的铜酞菁-苝二酰亚胺为模型体系。设计合成了六种不同的苝二酰亚胺衍生物,选取了两种侧链取代基不同的铜酞菁衍生物,建立了喷雾TiO2膜电极实验装置;制备了铜酞菁和苝二酰亚胺的双染料体系以及各自的单染料体系,对其光电转换性能参数进行了测试和研究,考察了分子结构的变化(主要是分子侧链取代基团的改变)对体系光电转换性能参数的影响。此外还采用Gaussian98程序对体系中分子轨道的能量进行了计算,运用量子化学手段讨论了分子轨道能量的匹配情况与光电转换性能的关系。实验结果表明,由于铜酞菁和苝二酰亚胺分子侧链取代基团不同,体系的开路电压、最大光电流密度和单色光光电转换效率都发生显著变化。在双染料体系中,给体分子不变,受体分子的取代基由吸电子基团变为推电子基团可以提高体系的光电转换性能,最高可超过90%。而当受体分子不变,给体分子的取代基由推电子基团变为吸电子基团也可以提高体系的光电转换性能,最高可超过50%。在单染料体系中,带有推电子侧基的给体分子体系对电子的转移和传输有利,体系的光电转换性能最大可以提高一个数量级。这说明给受、体分子之间侧链取代基团的变化会影响体系的光电转换性能。因此,选择光电转换功能体系工作物质的原则是:⑴在考虑工作物质的吸收波长和分子间轨道能量的匹配情况外,还要考虑工作物质的分子结构对电子转移和传输的影响;⑵在双染料体系中,带有吸电子侧基的给体分子与带有推电子侧基的受体分子组合成的(受体-给体-受体)-(给体-受体-给体),即(a-D-a)-(d-A-d)结构,有利于体系的电子转移和传输,可以提高体系的光电转换性能;⑶在单染料体系中,带有推电子侧基的给体分子体系(d-D-d)对电子的转移和传输有利,可以提高体系的光电转换性能。更多还原

【Abstract】 Characteristic of electron transporting is a determinative factor to valuethe performances of photoelectric conversion systems. In the organic photo-electric conversion functional systems, this kind of characteristic lies on theinteraction between different molecules of working materials, which isdecided by the molecular structures.Cuprum phthalocyanine/perylene diimide, a system commonly used inthe research of organic solar cell, was selecteded as a model to check therelationship between the changes of molecular structures (mainly the changesof their substituents) and photoelectric conversion parameters. Six kinds ofperylene diimide derivatives were designed and consequently synthesized,and two types of cuprum phthalocyanine derivatives with differentsubstituents were selected. We also designed spray titanium dioxide filmelectrode experimental device. Accordingly, di-dye and mono-dyephotoelectric conversion systems made of cuprum phthalocyanine derivativesand perylene diimide derivatives were prepared and their photoelectricconversion parameters were measured. Finally, molecular orbit energy wascalculated by Gaussian98 program, and relationships between the case ofmolecular orbital energy matching and the characteristics of photoelectricconversion in the di-dye and mono-dye systems were discussed.The results showed that because of the difference of substituents inphthalocyanine/perylene diimide systems, their open-circuit voltage, photo-current density and incident monochromatic photon-to-current conversionefficiency (IPCE) changed markedly. When electron-donor molecule keptunchanged in the di-dye systems, photoelectric conversion characteristicswere improved with the substituents of electron-acceptor molecule changingfrom electron withdrawing groups to electron donating groups, and whenelectron-acceptor molecule kept unchanged, characteristics of photoelectricconversion were improved with changing the substituents of electron-donormolecule from electron donating groups to electron withdrawing groups. Inthe mono-dye systems, electron-donor molecules with substituents of electrondonating groups had predominance of transporting electrons, which could alsoimprove the photoelectric conversion characteristics. These results showedthat the changes of substituents between electron-donor and electron-acceptormolecules had important effects on photoelectric conversion characteristics.Therefore, the criteria to select working materials in the organic photo-electric conversion functional systems are as following: first, the effects onelectron transporting caused by molecular structures of working materialsshould be considered as well as absorption wavelengths of working materialsand the case of molecular orbital matching between those working materials;second, electron-donor molecules with electron withdrawing substituentscombined with electron-acceptor molecules having electron donatingsubstituents could form a structure of donor-accptor-donor/accptor-donor-accptor(a-D-a/d-A-a), which would favor the process of electron transport-ing and then improve the characteristics of photoelectric conversion in di-dyesystems;last, in mono-dye systems, electron-donor molecules withsubstituents of electron donating groups have predominance of transportingelectrons, which could improve the photoelectric conversion characteristics.更多还原