有机小分子受体材料萘单酰亚胺的合成以及在高开路电压太阳能电池中的应用

Organic small molecule acceptor photovoltaic materials have made great progress in recent years, due to their advantages of easy purification, fixed molecular weight, easier to tune electronic energy level, absorption spectra and electron mobility. Naphthalene monoimides-based n-type small molecules are a new class of acceptor materials, and have become the research focus recently, due to that it possess broad absorption, higher LUMO level and higher electron mobility. However, the number and the diversity of the Naphthalene monoimides-based organic small molecules which can be used as acceptor for high open-circuit voltage OSCs are still quite far behind the requirement for non-fullerene OSCs. In addition, too thin active layer and poorer film-forming properties of the small molecules limited the large area fabrication and application of the OSCs based on the small molecules. Therefore, this project mainly focuses on developing Naphthalene monoimides-based organic small molecular acceptor materials with better film-forming properties. A series of n-type D-A structured organic small molecules based on Naphthalene monoimides acceptor unit and fluorene, carbazole or benzo[1,2-b:4,5-b']dithiophene (BDT) donor unit will be synthesized. The absorption, electronic energy levels, electron mobility and film-forming properties of the small molecules will be effectively adjusted by changing the diverse acceptor units or attaching the different side chains on BDT in order to attain the better application for the OSCs. Furthermore, the structure-properties relationship of the small molecule acceptors will be investigated.

有机小分子受体光伏材料具有易纯化、确定分子量、吸收光谱以及能级和迁移率更易调控等优点，近几年得到迅猛发展。萘单酰亚胺小分子是一类新的受体材料，其具有宽吸收，高LUMO能级和高电子迁移率，用于非富勒烯太阳能电池能获得高的开路电压，成为目前小分子光伏材料研究的热点。但是，文献已报道的萘单酰亚胺小分子受体光伏材料数量和种类都比较少，在很大程度上限制其快速发展。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萘单酰亚胺小分子受体材料进行研究，设计一系列基于萘单酰亚胺为受体单元，芴、咔唑和苯并二噻吩为给体单元的具有D-A结构的n-型有机小分子。通过调整不同的给体单元、引入不同侧链对小分子的成膜性、吸收、电子能级以及电子迁移率进行有效调节，以期能够很好的应用于高开路电压有机太阳能电池中；同时，探索小分子结构与性能的关系。

该项目在J. Mater. Chem. A, ACS Mater. Interfaces, China Chem. Lett.等期刊上发表SCI论文6篇，其中影响因子大于3以上3篇，包括2篇一区，一篇二区以及3篇三区文章。通过在萘单酰亚胺的3,6位引入二溴构建受体单元，且建立D-A聚合物受体，调控聚合物的吸收、能级以及电荷迁移率（J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 276–281）。通过在BDT结构单元的噻吩侧链上引入硫醚键调节稠环电子受体ITIC-S的吸收、电化学、热稳定性、形貌、迁移率以及结晶性，进而提高器件性能（ACS Appl. Mater. Interfaces 2019, 11, 32218−32224）。通过在ITIC-S分子的基础上，引入F原子来调控分子ITIC-SF的吸收光谱、电化学、形貌，同时，使用含有相同给体单元BDT-SF的D-A聚合物给体PBDB-SF和ITIC-SF电子受体获得12.1%的能量转换效率和超过1.0 V的开路电压（J. Mater. Chem. A, 2019, 7, 26351–26357）。通过在苝酰亚胺（PDI）的N端引入半氟烷基来调整PDI分子不好的溶解性以及提高其电子迁移率，并构建D-A聚合物受体（J. Polym. Sci.,Part A: Polym. Chem. 2018, 56, 116–124）。通过在聚合物给体PBDB-T中添加不同含量的二氟BT受体结构单元，构建无规共轭聚合物给体，并调整其吸收光谱、电子能级、形貌和电子迁移率，最后，考察分子结构与器件性能之间的关系（Chinese Chemical Letters, 2019, 30, 1161–1167）。