基于三嗪缺电子单元宽带隙聚合物给体材料的合成及光伏性能OA

Reducing the costs of photovoltaic material of organic solar cells is an urgent problem to be solved for their industrial production.Here we synthesized a triazine-based electron-deficient building block(BTTz)with a simple structure and low synthetic costs,and then developed a novel wide-bandgap polymer donor poly 2,6-(3,3′-difluoro)bithiophene-alt-2,4-bis(4-(2-butyloctyl)thiophen-2-yl)-6-methoxy-1,3,5-triazine(PDFBTTz)by combining with easily available 3,3'-difluoro-2,2'-bithiophene(DFT).It was characterized by thermogravimetric analysis,ultraviolet-visible absorption spectroscopy and cyclic voltammetry,etc.Results showed that the PDFBTTz exhibits an absorption range of 350-600 nm with a wide bandgap about 2.06 eV and a suitable highest occupied molecular orbit energy level(-5.49 eV),which are complementary with those of small-molecule electron acceptor IT-4F.As a result,the PDFBTTz-based polymer solar cell shows a modest power conversion efficiency of 3.49%with open-circuit voltage of 0.75 V,a short-circuit current density of 10.89 mA·cm-2,and a filling factor of 43.36%.These results indicate that the BTTz is a promising building block to construct wide-bandgap polymers,and further adjustment of molecular structure is expected to generate more efficient polymer donor materials.