主链液晶共轭聚合物模板中原位构筑稳定有序杂化本体异质结及其光伏电池

In this project, we propose to design and synthesize a serie of novel mainchain liquid crystal (LC) conjugated polythiophene derivatives with olefin groups at the end of alkyl side chain, acting as crosslinking sites. We are able to effectively control the micro-morphology and alignment direction of the films of the LC polymers by application of electric and magnetic fields. Combined with the coordination between the sulfur atom in the main chain of LC polymer and the Cd2+, the Cd2+ can be targeted to vicinity of LC polymer mainchain. Meanwhile, employing the approach based on controlled in situ thermal decomposition, the CdS nanocrystals can be in suit grown in the ordered microstructure LC polymer template. The composites prepared by this approach not only achieve the ordered micromorphology of LC polymer, but also the homo- and ordered- disperse of CdS nanocrystal in the LC polymer domains. Without using any surfactants or organic ligands, this approach can effectively suppress the macroscopical phase separation of those composites, hence obtaining ordered microstructure bulk heterojunction. The relationship between the nucleation and growth of CdS nanocrystal and ordered LC polymer template will be investigated particularly to accomplish the excellent control concerning the sizes, morphologies and distributions of CdS nanocrystal. We will understand in depth the influence of the microstructure of hybrid photovoltaic device active layers on the exciton separation efficiency, free charge carrier transportation and the photoelectric conversion efficiency (PCE). The effect of crosslinking of olefin groups at side chain of LC polymer on the stabilities of our hybrid photovoltaic devices are also supposed to be investaged. Finally, hybrid photovoltaic devices with high PCE and stabilities will be fabricated in this proposal.

设计一系列主链型液晶共轭聚噻吩，并在聚合物侧链上引入不饱和双键。利用液晶聚合物自发取向和电场磁场响应特性，对聚合物薄膜微观形态和取向方向进行调控。结合利用液晶聚合物主链上的硫原子与Cd2+的配位作用，将Cd2+"靶向定位"到液晶聚合物主链附近。同时采用热解法，在微观结构稳定有序的聚合物模板中原位生长CdS纳米晶。该法所得到的杂化材料既可以实现液晶聚合物有机相的微观结构有序性，又可以实现CdS纳米晶在有机相中的均匀有序分布。在不使用表面活性剂或有机配体的情况下，有效地抑制了宏观相分离的发生，获得微观结构有序的本体异质结结构。详细研究有序液晶聚合物模板与CdS纳米晶成核、生长之间的关系，从而达到对纳米晶大小、形貌及分布的调控作用。深入理解杂化薄膜的微观结构对激子分离效率、自由载流子输运及光电转换效率的影响。探讨不饱和双键交联对器件稳定性影响，制备具有高光电转换效率的、高稳定性的杂化太阳能电池。

该项目在国际权威刊物如Adv. Funct. Mater. (IF: 11.382); Chem. Mater. (IF: 9.407); Macromolecules (IF: 5.554); J. Mater. Chem. A (IF: 8.262)等国际权威刊物上相继发表论文60篇，其中影响因子大于3 以上55篇，影响因子大于5 以上30篇。2013-2016发表论文累计他引363次，被Science, Chem. Rev., Chem. Soc. Rev., Energy Environ. Sci., Angew. Chem. Int. Ed.等期刊引用和详细点评，New J Chem (2013)为当月Hot article，Chem Mater (2013)他引22次，ACS Appl Mater Interfaces (2013)他引30次，J Phys Chem C (2013)他引20次。第1完成人获省自然科学二等奖1项，第4完成人获省自然科学二等奖1项，获授权发明专利2项。提出了热致液晶共轭聚合物为模板原位生长纳米晶，控制纳米晶尺寸和形貌，提高杂化器件光电转化效率(Chem. Eur. J. 2014, Solar Energy 2016)。嵌段自组装原位制备杂化纳米纤维结构，最大化异质结界面(Macromolecules 2014, J. Mater. Chem. 2011)。嵌段共轭聚合物通过弱键协同自组装，构建双连续取向杂化和非杂化异质结界面，实现异质结界面桥联关系，提高界面激子分离效率(J. Mater. Chem. A 2013, ACS Appl Mater Interfaces 2014l, 2013s, 2013x, Polym. Chem. 2014, J. Mater. Chem. C 2014)。侧链嵌段聚噻吩自组装调控异质结界面，改善电极界面欧姆接触，调节电极功函，器件效率提高至7.3%(Chem Mater 2013, J. Mater. Chem. C 2014)。共轭聚电解质-离子液晶复合物形成偶极子在电场作用下能可逆快速取向并形成偶极矩，全溶液加工器件效率提高至8.5%(Adv Funct Mater 2014, Macromolecules 2014, J. Phys. Chem 2013)。