基于富勒烯衍生物界面修饰材料发展高效有机太阳能电池器件

Polymer solar cells (PSCs) have potential for industrial production because of the advantage of low-cost, light-weight and easy to fabricate in large-area with flexibility. At present, the best reported power conversion efficiency (PCE) for single organic solar cells has exceeded 10% for commercial application, which was driven mostly by the introduction of interfacial materials to decrease the work function of electrode. A number of studies have indicated that the interfacial materials between electrode and active layer can help form ohmic contact and improve the energy band and electric properties as well as prevent active layer from separating from electrode. As the most popular acceptors, fullerene derivatives with tunable energy level, good electron affinity and excellent compatibility have become a kind of important interfacial materials. However, the extremely limited reports on fullerene-based interfacial materials were facing the weakness of being complicated to synthesis and difficult to purifiy, which hinder their further applications. Meanwhile, an theory to guide the design of fullerene-based interfacial materials is desired to this day. In this context, the project is planned to design a series of facile fullerene-based and endohedral metallofullerene-based interfacial materials for improved PCE of PSCs and deeply investigate the relationship between the molecular structure and its property to provide theoretical guidance for designing high-efficient fullerene-based interfacial materials.

有机薄膜太阳能电池因成本低、质量轻、制作工艺简单、可大面积柔性制备等巨大优势而备受关注。目前，单结太阳能电池能量转换效率已突破有望商业化的10%，而实现这一突破的重要推动因素之一就是引入合适的界面修饰材料有效降低了电极的功函数。多项研究表明在吸收层和电极之间引入适宜的界面材料有助于形成欧姆接触，改善界面处的能带和电学性质，防止电极和吸收层的脱离。作为最受认可的受体材料，富勒烯衍生物同时具有的可调能级结构、良好电子亲和势以及优异兼容性等优点，又使其成为电极与受体材料之间一类重要的界面修饰材料。然而，目前已报道的富勒烯界面修饰材料还十分有限且存在合成复杂、成本较高等问题，同时缺乏较完整的理论来指导此类界面修饰材料的设计。本项目拟设计合成多种富勒烯及金属富勒烯衍生物界面修饰材料，进一步提高聚合物太阳能电池效率，深入研究其结构与性能的关系，为富勒烯界面修饰材料设计提供理论指导。

设计制备了ITIC-Th1、IDCIC、INIC等三种新型非富勒烯小分子受体材料，所构筑的光伏器件效率在当时都取得了突破性进展。设计制备基于PTB7-Th:PffBT4T-2OD:PC71BM三元体系的有机太阳能光伏电池。通过仔细调控结晶性不同的两种给体材料的比例，深入研究不同PffBT4T-2OD添加比例对器件光伏参数、光电转换过程和形貌的影响，揭示了器件形貌-性能的关系。同时揭示了侧链长度影响活性层形貌及器件性能的内在原因，最后对不同构型小分子受体的瞬态吸收光谱及非线性光学性质进行了对比性研究，发现分子构型对分子光学性质具有重要影响。