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设计和合成结构新颖的聚合物太阳能电池给体材料是有机电子学的热点研究领域.首先利用二噻吩取代的苯并二噻吩(DBDT)作为富电子结构单元,吡咯并吡咯二酮(DPP)作为缺电子单元构筑了一种新的聚合物太阳能电池电子给体材料(PDBDTDPP),然后以[6,6]-苯基-C61-丁酸甲酯(PC61BM)作为电子受体,借助密度泛函理论(DFT)方法结合不相干的Marcus-Hush电荷传输模型,系统研究了PC61BM-DBDTDPPn=1,2,3,∞体系的分子结构、电子性质、光吸收性质、电荷转移的内重组能和外重组能、激子结合能、电荷传输积分、给体-受体界面上激子分离和电荷复合速率等性质,并利用线性回归方法分析了聚合物重复单元与其光伏性质的关系.结果表明,该聚合物具有较好的平面结构,低的最高占据分子轨道(HOMO)能级,在紫外-可见区具有宽且强的光学吸收、较大的激子束缚能(1.365 e V),小的激子分离内重组能(0.152 e V)和电荷复合内重组能(0.314 e V).在给体-受体界面上,激子分离速率高达1.073×1014 s-1,而电荷复合速率仅为1.797×108 s-1.相比较而言,激子分离速率比电荷复合速率高约6个数量级,表明在给体-受体界面上,光生激子具有很高的分离效率.总之,研究证明PDBDTDPP是一个非常有前途的聚合物太阳能电池给体材料,值得实验上进一步合成及器件化研究.理论研究不仅有助于更深入理解有机化合物结构与其光学、电子性质之间的关系,还可以为合理设计聚合物太阳能电池给体材料提供有价值的参考.
Designing and synthesizing novel polymer solar cell donor materials is a hot research field in organic electronics.Firstly, dithiophene-substituted benzodithiophene (DBDT) was used as the electron-rich unit, and diketopyrrolopyrrole (DPP) A novel polymer solar cell electron donor material (PDBDTDPP) was constructed by electron-deficient unit, and then with [6,6] -phenyl-C61-methyl butyrate (PC61BM) as electron acceptor. The DFT method combined with the irrelevant Marcus-Hush charge transfer model systematically studied the molecular structure, electronic properties, optical absorption properties, internal recombination energy of charge transfer, and the molecular structure of PC61BM-DBDTDPPn = 1, Recombination energy, exciton binding energy, charge transport integral, exciton separation and charge recombination rate at the donor-acceptor interface, and the relationship between the polymer repeat units and their photovoltaic properties was analyzed by linear regression analysis. The results show that the The polymer has a good planar structure, a low highest occupied molecular orbital (HOMO) level, a broad and strong optical absorption in the UV-visible region, a large exciton binding energy (1.365 eV), a small stimulus Sub-separation within the recombinant energy ( 0.152 eV) and charge recombination (0.314 eV). At the donor-acceptor interface, the exciton separation rate was 1.073 × 1014 s-1 and the charge recombination rate was only 1.797 × 108 s-1. In comparison, the exciton separation rate is about six orders of magnitude higher than the charge recombination rate, indicating that photogenerated excitons have a high separation efficiency at the donor-acceptor interface.In summary, studies have shown that PDBDTDPP is a very promising Polymer solar cell donor material, it is worth further experimental synthesis and device research.The theoretical study not only helps to better understand the relationship between the structure of organic compounds and their optical, electronic properties, but also for the rational design of polymer solar cells Body material provides a valuable reference.