PCBM浇注电聚合纳米网格窄带隙聚合物构筑倒置太阳能电池及光伏性能研究

Narrow bandgap polymers are the key to improve the power conversion efficiency and also the focus of research in the polymer solar cells (PSCs). At present, the balanced tuning of the absorption spectra, energy levels, carrier mobility and morphology of active layers in the narrow bandgap polymers is still the main difficult problem to achieve further breakthrough of PSC power conversion efficiencies. By drawing on the characteristics of covalent organic frameworks (COFs) molecules based on the high carrier mobility and efficient charge transfer to PCBM and adopting similar COFs unit design, three series of novel nanogrid narrow bandgap polymers by alternating donating (D) unit with D unit to form backbone with bridged accepting unit can be electropolymerized on the surface of nanofilm materials in this project. The synthetic routes of the polymers will be expored. The influence of bearing different nanogrid units in the polymers on the their absorption, energy level, hole mobility and stacking with PCBM will be stuied. The inverted solar cells will be prepared by pouring process. By characterization and optimization of solar devices, we will study the influene of the nanogrid narrow bandgap polymers upon device performance. This project is importanct to explore the design concept for narrow bandgap polymers and promote high-efficiency PSCs.

窄带隙聚合物是提升聚合物电池光电转化效率的关键，也是聚合物电池研究的核心部分。如何均衡调控窄带隙聚合物的吸收光谱、能级排列、载流子传输以及活性层形貌，进一步突破当前效率瓶颈成为科学研究的难点。本课题旨在借鉴共价有机框架（COFs）分子高载流子传输及和PCBM高效电荷转移的特性，引入类COFs分子纳米单元格的设计理念，拟在纳米薄膜材料表面通过电聚合设计构筑以供体单元交替为主链、受体单元为桥联的新型纳米网格窄带隙聚合物。探索该类聚合物的通适合成路线；考察不同纳米网格单元对聚合物光谱拓展和能级排列的影响；研究PCBM在纳米网格单元中的嵌入情况和聚合物/PCBM膜的堆积方式，探讨纳米网格单元对聚合物载流子传输的影响；采用浇注工艺制备倒置结构太阳能电池，通过器件性能表征及优化，考察纳米网格单元对聚合物光伏性能的影响。该课题在探索窄带隙聚合物的结构创新设计，推进高效率聚合物电池的研究具有积极的意义。

以聚合物/钙钛矿太阳能电池为代表的第三代太阳能电池因可以制备成质轻超薄的大面积柔性器件引起了广泛的关注。对于聚合物太阳能电池而言，仍需要均衡调控材料分子结构设计中的供体/受体的光谱配伍、供体/受体的能级匹配以及光生电荷的传输、活性层的相分离形貌稳定等诸多问题，实现效率瓶颈的进一步突破；对于钙钛矿太阳能电池，设计开发高迁移率、能级匹配、回滞小的免掺杂空穴传输层材料是其性能提升的关键。本项目设计构筑了系列基于苯并二环戊二烯二噻吩为核的A-D-A型非富勒烯受体，通过器件工程和器件结构设计等方面优化，获得光电转化效率超过12.65%的有机聚合物太阳能电池，为当时基于苯并二环戊二烯二噻吩为核的A-D-A型非富勒烯受体报道的最高效率。此外，设计构筑基于噻吩或苯环桥联芴单元接枝三苯胺甲氧基的免掺杂空穴传输层材料。密度泛函理论揭示噻吩环桥联空穴传输层材料在钙钛矿界面上具有很强的硫-铅相互作用。基于噻吩环桥联的空穴传输层材料构筑倒置器件获得了最高为17.57%的光电转化效率。通过深入研究供体、受体及空穴传输层材料分子结构与器件光伏性能的之间构效关系，获得面向高效率有机太阳能电池/钙钛矿电池的分子结构设计新方法。