含多个稠环受体单元的D-An型聚合物给体材料的设计合成与光伏性能研究

Organic solar cells (OSCs) attract much attention due to the advantages of light-weight, flexibility and roll-to-roll fabrication. Recently, the power conversion efficiency (PCE) of single OSCs has achieved 12% due to rapid development of nonfullerene acceptors. However, as the other important composition in the active layer, the development of donor materials desiderates new strategy. We put forward the concept of D-An-type polymer donors containing multiple fusing-ring acceptor units to pursue highly efficient OSCs. We will copolymerize the donor unit with the multiple fuse-ring lactam or imide acceptor unit to improve electron-withdrawing components in polymers, which enhances intramolecular charge transfer effect and decreases the bandgap and energy levels of the polymers, thus affording high performance polymer donors with deep HOMO energy level, narrow bandgap and high mobility, and achieving high Voc, Jsc and FF in solar cells simultaneously. This project will be carried out from three aspects as following: (1) the development of D-A2-type polymer donors containing two fused-ring lactam acceptor units; (2) the development of D-A2-type polymer donors containing two fused-ring imide acceptor units; (3) the development of D-An-type polymer donors containing multiple fused-ring acceptor units. Based on this work, we will develop a series of high performance D-An-type polymer donors and achieve breakthrough in power conversion efficiency of solar cells.

有机太阳能电池具有质轻、柔性、可卷对卷制备等优点而备受关注。基于非富勒烯受体的快速发展，单节电池效率已超过12%。然而，作为活性层另一重要组成，给体材料的发展亟需新思路。围绕提高太阳能电池能量转化效率大目标，本项目提出含多个稠环受体单元的D-An型聚合物给体的构想。通过给体单元单体（D）与含多个内酰胺或酰亚胺稠环受体单元的单体（An）共聚，增加分子中拉电子单元成分，促进分子内电荷转移，同时降低聚合物带隙与能级，获得窄带隙、深HOMO能级、高迁移率的高性能聚合物给体，有望同时提高短路电流、开路电压和填充因子。本项目拟开展以下三个方面研究：（1）含两个内酰胺稠环受体单元的D-A2型聚合物给体研制；（2）含两个酰亚胺稠环受体单元的D-A2型聚合物给体研制；（3）含多个稠环受体单元的D-An型聚合物给体研制。通过实施本项目，有望获得一系列性能优异的D-An型聚合物给体，实现电池效率的突破。

基于近几年有机太阳能电池的飞速发展，我们及时抓住研究热点，主要从聚合物给体和小分子受体出发，开展如下研究：1）开发了多种D-A2型中等带隙聚合物给体（如PBTDBT, PBTDFBT），与传统富勒烯受体PC71BM匹配，电池效率接近10%，远高于同系列的传统D-A型聚合物给体，接近聚合物/富勒烯体系的最高水平。这说明本项目申请书提出的D-An型聚合物给体设计思路，提高电池效率的策略是可行的。2）开发了一系列大平面稠环给体单元构筑多种窄带隙、在红外区具有强吸收的小分子受体（如IUIC-O, IUIC-T, IDCIC等），与高性能的宽带隙聚合物给体匹配，电池效率超过13%，为此类小分子受体的最高效率之一。这说明扩展中心给体单元Π共轭结构是构筑高效率小分子受体的有效策略。3）开发了一种氧化还原-PH双响应的二硫键与钙离子掺杂的二氧化硅纳米颗粒（BT-Ca-MSN）作为抗癌药物的载体，表现出良好的生物可降解性且无明显生物毒性，与盐酸阿霉素起协同作用显著提高其抗癌效果。这一结果说明我们开发的BT-Ca-MSN纳米颗粒作为载体在癌症治疗方面具有很好的应用潜力。