科研之友
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摘要
The effect of nitrogen insertion in a benzothiadiazole (BT) moiety was investigated via the synthesis of a novel copolymer based on dithienosilole (DTS) and pyridalthiadiazole (PT), the heterocyclic counterpart. Stille cross coupling of the electron rich and electron poor units yields poly[(4, 4'-didodecyldithieno[3, 2-b: 2', 3'-d] silole-2, 6-diyl)-alt-(2, 1, 3-pyridalthiadiazole-4, 7-diyl), a nonsoluble polymer. Dense pi-pi stacking interactions that inhibited polymer solubility were cured by the introduction of two solubilizing hexylthiophene spacers, and a new soluble low-bandgap copolymer, namely poly[(4, 4'-didodecyldithieno[3, 2-b: 2', 3'-d] silole-2, 6-diyl)-alt-{4, 7-bis[2-(3-hexyl) thienyl]-2, 1, 3-pyridalthiadiazole5, 5'-diyl}] (PDTSDTPT), was alternatively obtained. For reasons of comparison, the corresponding oligomer, i.e., ODTSDTPT, was also synthesized. Their chemical, thermal, optical, electrical, and electrochemical properties were investigated. UV-visible spectroscopy revealed that PDTSDTPT alternating copolymer is more absorbing than its BT analog. It has a lower optical bandgap, higher absorptivity, and red-shifted absorption spectrum into the near-infrared region up to 900 nm. Photovoltaic applicability was investigated for PDTSDTPT and its derived oligomer in bulk heterojunction solar cells employing PC60BM, [6,6]-phenyl-C-60 butyric acid methyl ester, as the n-type semiconductor. Significant improvement of open-circuit voltage was evidenced with PT-based materials. The short-circuit current (J(SC)) and fill factor (FF), however, remain a material of continuous improvement by morphology control.
- 出版日期2017-7
- 单位中国地震局
