含硼氧配位键的缺电子单元及高分子电子受体

Compared to the well-developed polymer electron donors, the quantities of polymer electron acceptors are very limited, which have restricted the development of polymer solar cells. Currently, The typical polymer electron acceptors composed of electron-deficient units are mainly based on imide structure (O=C-N). Recently, novel electron-deficient units based on boron-nitrogen coordination bond (B←N) have been designed and showed unique electron structure. This project aims to develop another kind of electron-deficient units based on boron-oxygen coordination bond (B←O=C) by combining the structure features of imide moiety and B←N unit. The electron-deficient properties of carbonyl group can be strengthened by B←O=C unit which is formed through the vacant p-orbital of boron atom being occupied by the lone pair electrons of oxygen atom. Based on this principle, new electron-deficient units containing boron-oxygen coordination bond will be designed. Then we will develop the polymer electron acceptors with low-lying and tunable LUMO energy levels by choosing different comonomers. The research will reveal the rule between the unit structures and properties, as well as the relationship between structures of electron acceptors and device performances. It will provide research foundation for the further development of novel electron-deficient units and excellent electron acceptors based on the boron-oxygen coordination bond.

相比于大量开发的高分子电子给体，高分子电子受体的种类少、数量有限，限制了高分子太阳能电池的发展。目前，用于构建高效的高分子电子受体的缺电子单元主要基于酰胺基团（O=C‒N）。近期，基于硼氮配位键（B←N）的缺电子单元被设计、开发，并表现出独特的电子结构。本项目旨在结合两者（O=C‒N和B←N）的结构特点，利用硼原子的空p轨道和羰基上氧原子的孤对电子形成硼氧配位键（B←O=C）来加强原有羰基的缺电子性质，基于这一原理开发另一类含硼氧配位键的新型缺电子单元，然后与具有不同推拉电子性质的单元共聚，发展一系列LUMO能级低且可调的高分子电子受体。揭示出此类缺电子单元的结构与性质的变化规律、高分子电子受体的结构与其器件效率的关系。为开发含硼氧配位键的新型缺电子单元和高效的电子受体提供研究基础。

太阳能电池、燃料电池等被认为是未来重要的新一代主要供能电源，受到国际学术界和产业界的广泛关注。本项目围绕“有机硼功能材料化学”这一核心主题，面向新能源新材料研究方向，探索有机化合物的分子结构特性与光-电、化学-电转换效率之间的关系。具体采用硼原子的缺电子性质，通过调控电荷分布和能级结构构建特色功能B←N键分子体系，开发出一类新型能源材料。一方面，开发出的有机硼高分子电子受体材料解决了双硼氮桥联联吡啶高分子受体材料体系填充因子低的问题。另一方面，提出采用B←N键发展结构可调、活性位点可控的杂环高分子氧还原电催化剂的设计思想，开发机理明确的高活性新型催化材料体系，并将非对称概念首次引入到氧还原电催化剂的结构设计中，采用化学合成策略，调节B←N键的位置和数量以及烷基侧链的长度，实现非对称分子结构的精确调控，为设计高性能新能源材料提供了新的策略。