苯并噻二唑为中心的A-π-A-π-A型小分子光伏材料合成与性能研究

Research of synthesis and properties of benzothiadiazole-based A-π-A-π-A-type small-molecule photovoltaic materials

以苯并噻二唑为中心给体,利用Suzuki偶联和Knoevengel缩合等经典有机反应将吸电子基团氟原子和氰基引入到分子末端,完成了两个未见报道的以苯并噻二唑为中心的A-π-A-π-A型小分子化合物2F-TT-BT和2CN-TT-BT的合成,其化学结构通过核磁和高分辨质谱予以证实.通过紫外-可见吸收光谱、电化学循环伏安法及密度泛函理论计算对其光物理和电化学性质进行了实验及理论的研究.研究表明,合成的小分子材料对太阳光的吸收可覆盖整个紫外-可见吸收范围,具有与PC61BM相匹配的HOMO和LUMO能级,满足了溶液过程有机太阳能电池制备的基本要求.初步探索了材料的光伏性能,以小分子2F-TT-BT为给体,制作了结构为ITO/PEDOT:PSS/2F-TT-BT:PC61BM(质量比1∶2)/Al的体异质结(BHJ)太阳能电池,能量转换效率为0.53%,实验结果表明此类小分子是潜在的有机太阳能电池材料.

Two novel benzothiadiazole-based small molecules with the electron-withdrawing fluorine atom and cyanogroup as ending-group, namely 2F-TT-BT and 2CN-TT-BT, were synthesized successfully by Suzuki coupling and Knoevengel condensation reaction,respectively.Their molecular structures were characterized by NMR and HRMS,and their properties were investigated by density functional theory （DFT ） calculations, UV-vis absorption spectroscopy and cyclic voltammetry experiments.The photophysical and electrochemical properties show that the synthesized compounds exhibit broad absorption range covering the whole UV-vis spectral region of the sunlight and keep appropriate HOMO and LUMO energy levels with PC61 BM to satisfy the basic requirements of solution-processable preparation for OSCs.Therefore,the photovoltaic （PV）property of 2F-TT-BT as donor was investigated by fabricating the bulk-heterojunction （BHJ）solar cells with a typical structure of ITO/PEDOT：PSS/2F-TT-BT：PC61 BM （mass ratio：1∶2）/Al.As a preliminary result, it reveals a performance with a PCE of 0.53%.The experimental results indicate that these small molecules are potential PV materials for OSCs.