A-D-A型有机小分子给体光伏材料的合成及其在太阳能电池中的应用

Organic small molecule donor photovoltaic materials have made great advancements in resent years, due to their advantages of easy purification, s easier to tune electronic energy level and charge carrier. Acceptor-Donor-Acceptor(A-D-A)-type small molecules have become the research focus, due to that A-D-A-type small molecules possess broad absorption, deep HOMO and coplanar conjugated structure. However, the number and the diversity of A-D-A-type small molecular donor photovoltaic materials are still quite far behind its development. In addition, too thin active layer and poorer film-forming properties of the small molecules limited the large area fabrication and application of the organic solar cells based on the small molecules. Based on this, this project mainly focuses on developing the A-D-A-type small molecule donor photovoltaic materials with better film-forming properties. A series of A-D-A-type organic small molecules based on benzo[1,2-b:4,5-b']dithiophene (BDT) donor unit and benzothiadiazole or [1,2,5]thiadiazolo[3,4-c]pyridine acceptor unit will be synthesized. The absorption, electron energy levels, hole mobility and film-forming properties of the small molecules will be effectively adjusted by changing the diverse acceptor units or attaching the different conjugated side chains on BDT in order to attain the better application for the organic solar cells. Furthermore, the relationship of small molecule structure and properties will be investigated.

有机小分子给体光伏材料具有易提纯、能级和迁移率更易调控等优点，最近几年得到了迅猛发展。受体-给体-受体（A-D-A）型小分子通常具有宽的吸收，深的HOMO能级、大的共平面，成为目前小分子光伏材料研究的热点。但是，文献已报道的A-D-A型小分子给体光伏材料数量和种类都比较少，在很大程度上限制了其快速发展。另外，当前研究的有机小分子材料薄的活性层厚度和较差的成膜性限制了有机小分子太阳能电池的大面积制备和实际应用。本项目着眼于对具有较好成膜性的A-D-A型小分子给体光伏材料进行研究，设计一系列基于苯并二噻吩为给体单元、苯并噻二唑或吡啶噻二唑为受体单元的A-D-A型线性平面小分子。通过调整不同的受体单元、引入不同共轭侧链对小分子的成膜性、吸收、电子能级以及空穴迁移率进行有效调节，以期能够很好的应用于有机太阳能电池中；同时，探索小分子结构与性能之间的关系。

有机小分子给体光伏材料具有易提纯、能级和迁移率更易调控等优点，最近几年得到了迅猛发展。受体-给体-受体（A-D-A）型小分子通常具有宽的吸收，深的HOMO能级、大的共平面，成为目前小分子光伏材料研究的热点。本项目着眼于对具有较好成膜性的A-D-A型给体光伏材料进行研究，设计合成了一系列基于苯并二噻吩的A-D-A型线性平面光伏材料。通过调整不同的受体单元、引入不同共轭侧链等手段对光伏材料的成膜性、吸收、电子能级以及空穴迁移率进行有效调节，获得了一系列高效的给体光伏材料，基于A-D-A型小分子光电转换效率超过了10%；同时，探索了光伏材料结构与性能之间的关系。研究过程中我们发现，线性共平面材料能有效降低器件活性层中富勒烯受体的含量，这有利于进一步降低器件的成本。我们将共平面理念应用到聚合物中，得到了同样的结果，从而证实这一理念的普适性，这对低成本、高效光伏器件的制备具有非常重要的指导意义。