基于可溶小分子给体的非富勒烯有机太阳能电池研究

Non-fullerene organic photovoltaic cells have become the research hotspot in organic photovoltaic fields, because of the problems of materials cost, device efficiency and lifetime of photovoltaic devices containing fullerene derivatives. This project conducts research on organic photovoltaic cells based on soluble small molecular donors and polymer acceptors, which will mainly focus on the following three aspects: 1) design and synthesis of novel soluble small molecular donors, research on the relationship between the molecular structures, band-gap, solubility and light-absorption; 2) research on the film morphology properties of active layer based on small molecular donors/polymer acceptors, investigate the effective molecular packing, phase separation and charge transfer; 3) structural design and evaluation of high efficiency non-fullerene organic solar cells, investigate the effect of interface modification on charge extraction and blocking of exiton. These research works will provide theoretical and experimental basis for tuning the optoelectronic properties of soluble small molecular donors, designing of high efficiency non-fullerene device structure and promoting the development of organic photovoltaic technology.

富勒烯及其衍生物在材料成本、电池器件效率及寿命等方面存在的固有问题，使得非富勒烯有机太阳能电池成为当前有机光伏领域研究的热点。本项目拟对非富勒烯有机太阳能电池中基于可溶小分子给体/聚合物受体太阳能电池开展以下三方面研究：1) 设计并合成新型可溶小分子给体材料，研究分子结构与能级、溶解性、光吸收之间的关系；2) 研究小分子给体/聚合物受体活性层的形貌调控，实现活性层内部的有效分子堆叠、相分离及电荷传输；3) 高效非富勒烯有机太阳电池的结构设计，研究界面修饰对活性层/电极界面的载流子提取及激子阻挡。以上研究将为调控可溶小分子给体材料光电性能、设计新型高效非富勒电池结构、促进有机太阳能电池技术的发展提供理论和实验基础。

随着近几年来非富勒烯受体的不断发展，非富勒烯有机太阳能电池的最高效率不断被刷新，最近已经突破18%，远远超过了富勒烯器件的水平。非富勒烯受体在吸收光谱以及电子能级上表现出极大的可调性，同时非富勒烯材料合成思路更加灵活，受限更小。通过合理的结构设计，已经能够实现低电压损耗和高电流输出，这是富勒烯受体不能比拟的。与效率的不断突破和新型有机分子的长足发展相比，非富勒烯太阳能电池器件工艺、稳定性、薄膜形貌等方面的研究还存在不足。针对这些不足，本项目开展了几方面工作：其一，设计合成设计新型可溶小分子材料，研究分子能级、溶解性、光吸收对三元器件性能的影响；其二，引入新型添加剂改善薄膜的形貌，增加器件的稳定性；其三，探索第三元材料与主体系的相互作用，不仅做到了拓宽吸收光谱，提高功率转换效率，还显著提高器件寿命。