化学学报 ›› 2016, Vol. 74 ›› Issue (8): 676-682.DOI: 10.6023/A16050268 上一篇    下一篇

研究论文

苯并噻二唑类电子受体材料分子设计与给-受体的理论匹配

邵绒, 杨鑫博, 尹世伟, 王文亮   

  1. 陕西省大分子科学重点实验室 陕西师范大学化学化工学院 西安 710119
  • 收稿日期:2016-05-30 出版日期:2016-08-15 发布日期:2016-08-10
  • 通讯作者: 王文亮 E-mail:wlwang@snnu.edu.cn
  • 基金资助:

    项目受国家自然科学基金(Nos. 21173139,21473108)和陕西省重点科技创新团队基金(No. 2013KCT-17)资助.

Molecular Design of Benzothiadiazole Derivatives Electron Acceptors and Matching of Donor-Acceptor Materials

Shao Rong, Yang Xinbo, Yin Shiwei, Wang Wenliang   

  1. Key Laboratory for Macromolecular Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an 710119, China
  • Received:2016-05-30 Online:2016-08-15 Published:2016-08-10
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Nos. 21173139, 21473108) and Shaanxi Innovative Team of Key Science and Technology (No. 2013KCT-17).

设计并理论预测了一系列A'-π-A-π-A'型苯并噻二唑衍生物电子受体分子的几何构型、前线轨道特征、吸光性质及电子重组能等信息,同时考察了丙酮、氯苯溶剂对其性质的影响. 在此基础上将性能优异的受体分子与特定给体分子组合构建给-受体(D-A)界面,通过计算给体HOMO与受体LUMO之间的电子耦合Vif,评估了D-A界面载流子的复合程度. 结果表明,合理选择取代基对核心受体苯并噻二唑进行修饰是调节LUMO能级和能隙的有效方法. 将平面性好的受体材料与非平面型给体材料搭配作为有机太阳能电池光活性层材料,有可能达到降低界面复合、减小光电压损失和提高开路电压的目的. 综合考虑ΔELVif,光吸收效率及溶剂化效应等因素,D1-1aγD1-2aγ组合有望成为电子迁移率高、在可见光和近红外区吸收宽、界面激子可以有效分离且不易复合的理想给-受体分子组合.

关键词: 苯并噻二唑, 电子受体分子, 给-受体界面, 电子耦合, 能量转换效率

To better understand the relationships between the microstructure and the optoelectronic characteristics of the electron acceptor and to meet the needs of donor-acceptor materials with excellent optical properties for solar cell, a series of acceptor molecules with A'-π-A-π-A' type are designed. In these molecules, the core framework of benzothiadiazole is used as an acceptor (A), three kinds of conjugated heterocyclics (A') with different abilities of electron-withdrawing and steric effects are applied as the terminals, and various conjugated structures, such as the double bond, thiophene, benzothiophene and vinyl thiophene, are utilized as π-bridge, respectively. Their geometric configurations, the characteristics of frontier molecular orbital, optical properties, as well as the electronic reorganization energy are predicted by DFT-B3LYP and TD-DFT-CAM-B3LYP. Solvent effects from acetone and chlorobenzene on molecular properties are studied. Furthermore, the Donor-Acceptor (D-A) interfaces are respectively constructed by combining the excellent acceptors with the selected two donors. The DFT-D3 method is used to scan the binding energy of D-A complex, in order to determine the stacked displacement of the interface. The degree of interface recombination is evaluated by calculating electronic coupling (Vif) between HOMO of donors and LUMO of acceptors. The results show that modifying benzothiadiazole with a reasonable substituent is an effective way to adjust LUMO energy levels and lead to the noticeable variation of the energy gap. Combining planar electron acceptor materials (A'-π-A-π-A' type) with non-planar electron donor materials (D), to form the optical active layer is a practical approach for preventing interface recombination and achieving high open-circuit voltage (Voc). Considering ΔEL, Vif, light absorption efficiency, and solvation effect, D1-1aγ and D1-2aγ combinations are the most promising candidates of optical active layer materials in organic solar cell.

Key words: benzothiadiazole derivatives, electronic acceptors, Donor-Acceptor interface, electronic coupling, the power conversion efficiency