Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, People's Republic of China.
School of Chemistry, College of Science, University of Tehran, Tehran, Iran.
J Mol Model. 2023 Jan 3;29(1):31. doi: 10.1007/s00894-022-05435-x.
Density functional theory (DFT) method was employed to investigate the electronic structure properties, excited state dynamics, charge transfer, and photovoltaic potential of benzo [1,2,5] thiadiazole fused to 3,7-dimethyl-3a,6,7,7b-tetrahydro-5H-thieno[2',3':4,5]thieno[3,2-b]pyrrole to form 3,9,12,13-tetramethyl-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2″,3″:4,5]pyrrolo[3.2-g]thieno[2',3':4,5]thieno[3,2-b]indole as the acceptor (A), bridge with thiophene as π-spacer to the donor moieties (D) which are 2,3-dihydrobenzo [b]thiophene-6-carboxylic acid (M4) and functionalized R, M1, M2, M3, and M5 to give a D-π-A-π-D. Here is the reverse combination for our molecules: the A-π-D-π-A type of chromophore configuration. It is also observed that tuning the dono-bridge configuration significantly increases the ease of charge transfer as the energy gap decreases in the order of 1.29 eV in M4 < 1.59 eV in M3 < 1.67 eV < 1.99 in M2 and 2.06 eV. The reorganization energy (RE) of M3 (0.0031) and M5 (0.0031) indicates an increase in the order of M3 > M5 > R > M2 > M4 > M1. The HOMO-LUMO indicates that the reactivity decreased, while the stability increased for the reference R at 0.990 eV, compared to the designed molecules M1-M5, with M1 being the least stable at 0.970 eV, while M4 exhibited the highest stability at 1.550 eV. The stability of the designed molecule decreased in the order of M4:1.550 > M3:1.257 > M5:1.197 > M2:1.010 > M1:0.970. Therefore, all results point to the electron-deficient core as an effective end-capped electron acceptor in M1-M5 compounds. As the ideal pair for successfully optimizing optoelectronic properties by reducing the HOMO-LUMO energy levels, reorganization energy, and binding energy and enhancing the absorption maximum and open-circuit voltage values in these designed molecules.
DFT and TDDFT calculations were performed with Gaussian 16 program. The modelled compounds were optimized fully using the CAM-B3LYP, WB97XD, B3LYP, and MPW1PW91 functionals with the 6-31 G (d,p) basis set. The graphs for the density of states were plotted using the PyMOlyze software. Other molecular properties like the transition density matrix (TDM) and electron density difference maps (EDD) were rendered via the Multiwfn software.
采用密度泛函理论（DFT）方法研究了苯并[1,2,5]噻二唑与 3,7-二甲基-3a,6,7,7b-四氢-5H-噻吩[2',3':4,5]噻吩[3,2-b]吡咯融合形成 3,9,12,13-四甲基-12,13-二氢-[1,2,5]噻二唑[3,4-e]噻吩[2″,3″:4,5]吡咯[3.2-g]噻吩[2',3':4,5]噻吩[3,2-b]吲哚作为受体（A），桥接噻吩作为给体部分（D），给体部分为 2,3-二氢苯并[b]噻吩-6-羧酸（M4）和功能化的 R、M1、M2、M3 和 M5，形成 D-π-A-π-D。这是我们分子的相反组合：A-π-D-π-A 型发色团构型。还观察到，通过调整供体-桥接构型，可以显著增加电荷转移的容易程度，因为能量间隙按 M4<1.59 eV<1.67 eV<1.99 eV 和 2.06 eV 的顺序减小。M3（0.0031）和 M5（0.0031）的重组能（RE）表明，M3>M5>R>M2>M4>M1 的顺序增加。HOMO-LUMO 表明，与参考 R（0.990 eV）相比，设计的分子 M1-M5 的反应性降低，稳定性增加，其中 M1 的稳定性最低（0.970 eV），而 M4 的稳定性最高（1.550 eV）。设计分子的稳定性按 M4：1.550>M3：1.257>M5：1.197>M2：1.010>M1：0.970 的顺序降低。因此，所有结果都表明，电子缺的核心是 M1-M5 化合物中有效的端封电子受体。作为通过降低 HOMO-LUMO 能级、重组能和结合能以及提高这些设计分子的吸收最大值和开路电压值来成功优化光电性能的理想对。
使用 Gaussian 16 程序进行 DFT 和 TDDFT 计算。使用 CAM-B3LYP、WB97XD、B3LYP 和 MPW1PW91 函数，在 6-31 G（d，p）基组上对模型化合物进行了完全优化。使用 PyMOlyze 软件绘制了态密度图。其他分子性质，如过渡密度矩阵（TDM）和电子密度差图（EDD），通过 Multiwfn 软件呈现。
