Wei Yaoyao, Li Yunzhi, Zhou Guangli, Liu Guokui, Leng Xia, Xia Qiying
School of Chemistry and Chemical Engineering, Linyi University, Linyi 276000, China.
School of Chemistry and Chemical Engineering, Linyi University, Linyi 276000, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2023 Feb 5;286:121925. doi: 10.1016/j.saa.2022.121925. Epub 2022 Sep 27.
The organic solar cells based on halogen-free components, have been the new favorites to develop green and renewable energy. PBDB-T and its derivatives are considered the superior electron donors to construct the solar cells. Although there are plenty of researches about them, the charge-transfer mechanisms and excitation energy transfers of relative organic solar cells are still unclear, the developments of photovoltaic devices are restricted consequently. In this work, we calculate the electronic structures and excited-state properties of PBDB-T, PBT1-C, PBT1-O and PBT1-S donors in the gas phase from the many-body Green's function theory. With BTP-IC and BTP-IS as the acceptors, we consider the Förster, Dexter, and overlap electronic couplings to compute the excitation energy transfers of the dimers. The ionization energies and excited-state energies of the four donors calculated by GW + BSE are in good agreement with experiments, and they are sensitive to the functionals in the computation. We find two charge transfer schemes. The thienyl of PBDB-T molecule makes its charge-transfer state at the lowest energy, and the total electronic coupling of PBDB-T based dimer is the strongest. The Dexter, and overlap types electronic couplings are significant to study the excitation energy transfer of organic heterojunctions. We provide a theoretical guide in the design and synthesis of higher-performance halogen-free donors.
基于无卤成分的有机太阳能电池已成为开发绿色可再生能源的新宠。PBDB-T及其衍生物被认为是构建太阳能电池的优质电子供体。尽管对它们有大量研究，但相关有机太阳能电池的电荷转移机制和激发能转移仍不明确，这 consequently 限制了光电器件的发展。在这项工作中，我们从多体格林函数理论计算了气相中PBDB-T、PBT1-C、PBT1-O和PBT1-S供体的电子结构和激发态性质。以BTP-IC和BTP-IS作为受体，我们考虑了Förster、Dexter和重叠电子耦合来计算二聚体的激发能转移。通过GW + BSE计算的四种供体的电离能和激发态能量与实验结果吻合良好，并且它们在计算中对泛函敏感。我们发现了两种电荷转移方案。PBDB-T分子的噻吩基使其电荷转移态处于最低能量，基于PBDB-T的二聚体的总电子耦合最强。Dexter和重叠类型的电子耦合对于研究有机异质结的激发能转移具有重要意义。我们为高性能无卤供体的设计和合成提供了理论指导。
