基于双电层理论的染料敏化太阳能电池用高效阳离子染料研究

Photo-sensitizer plays a vital role in absorbing sunlight and injecting electron into the conduction band of semiconductor in dye sensitized solar cells (DSC). In recent years, cationic dyes as promising metal-free organic sensitizers have attracted more and more attention because of their strong electron-withdrawing ability, excellent and tunable absorption in the red to near-infrared region as well as their high absorptivities (ca.100 000 M-1 cm-1).In this project, we plan to introduce N-(carboxymethyl)-pyridinium unit and N-(carboxymethyl)-isoquinoline unit, as electron acceptor and anchoring group, respectively into the dye structure to construct a series of novel D-π-A cationic sensitizers with near-infrared absorption. Meanwhile, we will also introduce the cationic group with strong electron-withdrawing ability and strong electron donor into the framework of "Type-II sensitizers", which use hydroxyl as anchoring group, to build a series of D-π-A cationic dyes with a stronger push-pull system than the previously reported Type-II dyes. In addition, the theory of "electric double layer" will be applied in the study of cationic sensitizers for the first time. By comparing with neutral dyes, we will have an insight into the influence of cationic dyes on some key DSC performance parameters, such as the charge injection efficiency, the electron transfer efficiency, the electron lifetime and so on, which will provide important implication and guidance for designing and fabricating more efficient dye sensitized solar cells.

在染料敏化太阳能电池(DSC)中，光敏染料起到吸收太阳光并向半导体导带注入电子的关键作用。阳离子染料作为近年来新兴的一类非金属有机光敏染料，因其优良的吸电子能力，非常高的摩尔消光系数，对长波长可见光及近红外光的良好吸收性能而备受关注。本项目拟将强吸电子基团N-羧甲基-吡啶阳离子和N-羧甲基-异喹啉阳离子分别引入到染料分子结构中，构建一系列新型的具有近红外吸收性能的D-π-A型阳离子光敏染料。另外，将首次将阳离子基团引入到"第二类DSC光敏染料"分子结构中，构建一系列具有强电子推拉体系的以"羟基"为吸附基团的D-π-A型阳离子光敏染料。同时，将首次将"双电层"理论引入到阳离子光敏染料的研究中，通过与中性染料的对比，了解阳离子光敏染料对DSC电池的电荷注入效率，电子扩散效率及电子寿命等一系列重要性能参数的影响，为设计更高效的DSC电池提供更深层次的理论指导。

在染料敏化太阳能电池(DSC)中，光敏染料起到吸收太阳光并向半导体导带注入电子的关键作用。阳离子染料作为近年来新兴的一类非金属有机光敏染料，因其优良的吸电子能力，非常高的摩尔消光系数，对长波长可见光及近红外光的良好吸收性能而备受关注。本项目将强吸电子基团N-羧甲基-吡啶阳离子和N-羧甲基-异喹啉阳离子分别引入到染料分子结构中，构建一系列新型的具有优秀吸光性能的D-π-A型阳离子光敏染料，同时，将将“双电层”理论引入到阳离子光敏染料的研究中，构成的DSC的光电转换效率最高达8.8%，在相同条件下，钌光敏染料(N719)制成的DSC效率为8.0%。首次将阳离子基团引入到“第二类DSC光敏染料”分子结构中，构建一系列具有强电子推拉体系的以“羟基”为吸附基团的D-π-A型阳离子光敏染料。