Theoretical Design of Perylene Diimide Dimers with Different Linkers and Bridged Positions as Promising Non-Fullerene Acceptors for Organic Photovoltaic Cells
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- 作者：Hang Yin ; Yun Geng ; Guang-Yan SunZhong-Min Su
- 刊名：Journal of Physical Chemistry C
- 出版年：2017
- 出版时间：February 2, 2017
- 年：2017
- 卷：121
- 期：4
- 页码：2125-2134
- 全文大小：607K
- ISSN：1932-7455
文摘
The intermolecular stacking and crystallization of perylene diimides (PDIs) has become research obstacles for small molecule acceptors (SMAs). For breaking molecular rigidity and planarity, it is an executable way to increase the distortion between two PDI units. A class of PDI dimers were designed via bridging different linkers in bay positions (1–1′ bridge) and headland positions (1–2′ bridge) to screen suitable acceptor materials for organic photovoltaic cells (OPVs). Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations were performed to investigate their electronic structures, open circuit voltage (VOC), driving forces (ΔEL-L), and some major parameters related to the short-circuit current density (JSC) such as absorption spectrum and carrier transport ability. Meanwhile, the intermolecular charge transfer (inter-CT) and charge recombination (inter-CR) rates were calculated for a further analysis on charge transfer properties at donor/acceptor (D/A) interface by employing the Marcus semiclassical model. The results manifest that the investigated 1–2′ bridged molecules possess low-lying LUMO energy levels, relatively bigger ΔEL-L, bathochromic-shifted absorption, as well as the strongest maximum absorption and more effective charge transport than 1–1′ bridged molecules. Surprisingly, compared with P3HT/(1–1′ bridged PDI dimers) interface, almost constant reorganization energy (λ), higher Gibbs free energy change of exciton dissociation (ΔGCT), and considerable inter-CT/inter-CR rates ratios (kinter-CT/kinter-CR) of P3HT/(1–2′ bridged PDI dimers) provides further evidence for that 1–2′ bridged PDI dimers as acceptors might perform higher efficiency in OPV device. Moreover, constructing NDT and DPPT as bridged linkers in PDI dimers as “push–pull” structures may rationally expect more favorable properties as acceptors in OPVs, which might provide theoretical guideline for the design and synthesis of new organic SMAs.