Department of Applied Chemistry, National Chiao Tung University, 1001 University Road, Hsin-Chu, 30010 Taiwan.
Chem Soc Rev. 2015 Mar 7;44(5):1113-54. doi: 10.1039/c4cs00250d.
Harvesting solar energy from sunlight to generate electricity is considered as one of the most important technologies to address the future sustainability of humans. Polymer solar cells (PSCs) have attracted tremendous interest and attention over the past two decades due to their potential advantage to be fabricated onto large area and light-weight flexible substrates by solution processing at a lower cost. PSCs based on the concept of bulk heterojunction (BHJ) configuration where an active layer comprises a composite of a p-type (donor) and an n-type (acceptor) material represents the most useful strategy to maximize the internal donor-acceptor interfacial area allowing for efficient charge separation. Fullerene derivatives such as [6,6]-phenyl-C61 or 71-butyric acid methyl ester (PCBM) are the ideal n-type materials ubiquitously used for BHJ solar cells. The major effort to develop photoactive materials is numerously focused on the p-type conjugated polymers which are generally synthesized by polymerization of electron-rich donor and electron-deficient acceptor monomers. Compared to the development of electron-deficient comonomers (acceptor segments), the development of electron-rich donor materials is considerably flourishing. Forced planarization by covalently fastening adjacent aromatic and heteroaromatic subunits leads to the formation of ladder-type conjugated structures which are capable of elongating effective conjugation, reducing the optical bandgap, promoting intermolecular π-π interactions and enhancing intrinsic charge mobility. In this review, we will summarize the recent progress on the development of various well-defined new ladder-type conjugated materials. These materials serve as the superb donor monomers to prepare a range of donor-acceptor semi-ladder copolymers with sufficient solution-processability for solar cell applications.
从太阳光中采集太阳能发电被认为是解决人类未来可持续性问题的最重要技术之一。在过去的二十年中，由于聚合物太阳能电池 (PSCs) 具有通过溶液处理在低成本下在大面积和轻量级柔性基板上制造的潜在优势，因此引起了极大的兴趣和关注。基于本体异质结 (BHJ) 配置概念的 PSCs，其中活性层由 p 型（供体）和 n 型（受体）材料的复合材料组成，代表了最大限度地增加内部供体-受体界面面积以实现有效电荷分离的最有用策略。富勒烯衍生物，如[6,6]-苯基-C61 或 71-丁酸甲酯（PCBM），是普遍用于 BHJ 太阳能电池的理想 n 型材料。开发光活性材料的主要努力集中在 p 型共轭聚合物上，这些聚合物通常通过富电子供体和缺电子受体单体的聚合来合成。与开发缺电子共聚单体（受体段）相比，富电子供体材料的开发相当繁荣。通过共价固定相邻的芳族和杂芳族亚基进行强制平面化导致形成梯形共轭结构，这能够延长有效共轭，降低光学带隙，促进分子间π-π相互作用并提高本征电荷迁移率。在这篇综述中，我们将总结最近在开发各种新型定义明确的梯形共轭材料方面的进展。这些材料作为极好的供体单体，可制备一系列具有足够溶液加工性的供体-受体半梯形共聚物，适用于太阳能电池应用。
