深HOMO能级非对称液晶小分子给体设计合成及光伏性能研究

液晶小分子给体在有机太阳能电池中表现出优异的自组装和电荷传输性能。但液晶小分子给体的强结晶使其全小分子体系活性层形貌精细化调控依旧面临困难，相对偏浅的HOMO能级也是限制性能提升的重要因素。本项目针对液晶小分子给体强结晶和HOMO能级偏浅性能缺陷导致的形貌精细化调控难及开路电压偏低的问题，提出吸电子基非对称修饰设计，构筑深HOMO能级非对称液晶小分子给体，通过调控分子能级、液晶等分子特性，达到精细化调控活性层形貌的目的，最终实现电池开路电压和效率同步提升的设想。首先，研究深HOMO能级非对称液晶小分子给体的设计合成方法，完成材料制备；其次，研究新材料半导体光电性能、液晶及薄膜形貌特征，探究构效关系；最后，研究基于新材料的高效太阳能电池设计制备方法，完成光伏性能的实验验证。该研究致力丰富高效液晶小分子给体种类的同时，提升该类分子在有机光伏领域效能作用的理论认识，为开发高性能电池器件奠定基础。

Liquid-crystalline small-molecule donors (LCSMDs) show excellent self-assembly and charge transfer performance in organic solar cells (OSCs). However, delicately fine-tuning the morphology involving only LCSMDs and small-molecule acceptors is an extremely challenging task, and the shallower HOMO energy level compared with polymer donor is another important factor for limiting the performance improvement of their photovoltaic devices. This project, focus on the abovementioned problems, tries to design and synthesis asymmetric LCSMDs with deep HOMO energy levels using asymmetrically modified electron-withdrawing groups, in order to regulate molecular properties, such as energy levels, liquid-crystal and so on, thus realizing delicately morphology control, and finally enhancing the open-circuit voltage and photoelectric conversion efficiency of OSCs. Firstly, we try to design asymmetric LCSMDs with deep HOMO energy levels through theoretical calculation, and prepare them via organic synthesis reactions. Secondly, we will characterize the semiconductive properties, liquid-crystalline peculiarity and film morphology of asymmetric LCSMDs, and try to clarify the relationship among them. Finally, the asymmetric LCSMDs will be applied in all-small-molecule OSCs, in order to gain the photovoltaic performance of asymmetric LCSMDs. The results of this project not only enrich the class of LCSMDs, but also improve the theoretical understanding about the effectiveness of LCSMDs using in OSCs, laying the foundation for developing high-performance OSCs.