Huang Jin-Dou, Li Wen-Liang, Wen Shu-Hao, Dong Bin
School of Physics and Materials Engineering, Dalian Nationalities University, Dalian, 116600, China.
J Comput Chem. 2015 Apr 15;36(10):695-706. doi: 10.1002/jcc.23825. Epub 2015 Feb 23.
Recently, diketopyrrolopyrrole (DPP)-based materials have attracted much interest due to their promising performance as a subunit in organic field effect transistors. Using density functional theory and charge-transport models, we investigated the electronic structure and microscopic charge transport properties of the cyanated bithiophene-functionalized DPP molecule (compound 1). First, we analyzed in detail the partition of the total relaxation (polaron) energy into the contributions from each vibrational mode and the influence of bond-parameter variations on the local electron-vibration coupling of compound 1, which well explains the effects of different functional groups on internal reorganization energy (λ). Then, we investigated the structural and electronic properties of compound 1 in its isolated molecular state and in the solid state form, and further simulated the angular resolution anisotropic mobility for both electron- and hole-transport using two different simulation methods: (i) the mobility orientation function proposed in our previous studies (method 1); and (ii) the master equation approach (method 2). The calculated electron-transfer mobility (0.00003-0.784 cm(2) V(-1) s(-1) from method 1 and 0.02-2.26 cm(2) V(-1) s(-1) from method 2) matched reasonably with the experimentally reported value (0.07-0.55 cm(2) V(-1) s(-1) ). To the best of our knowledge, this is the first time that the transport parameters of compound 1 were calculated in the context of band model and hopping models, and both calculation results suggest that the intrinsic hole mobility is higher than the corresponding intrinsic electron mobility. Our calculation results here will be instructive to further explore the potential of other higher DPP-containing quinoidal small molecules.
最近，基于二酮吡咯并吡咯（DPP）的材料因其在有机场效应晶体管中作为亚单元具有良好性能而备受关注。利用密度泛函理论和电荷传输模型，我们研究了氰化联噻吩功能化的DPP分子（化合物1）的电子结构和微观电荷传输性质。首先，我们详细分析了总弛豫（极化子）能量在各振动模式贡献中的分配情况以及键参数变化对化合物1局部电子 - 振动耦合的影响，这很好地解释了不同官能团对内部重组能（λ）的影响。然后，我们研究了化合物1在孤立分子状态和固态形式下的结构和电子性质，并使用两种不同的模拟方法进一步模拟了电子和空穴传输的角分辨率各向异性迁移率：（i）我们先前研究中提出的迁移率取向函数（方法1）；（ii）主方程方法（方法2）。计算得到的电子转移迁移率（方法1为0.00003 - 0.784 cm² V⁻¹ s⁻¹，方法2为0.02 - 2.26 cm² V⁻¹ s⁻¹）与实验报道值（0.07 - 0.55 cm² V⁻¹ s⁻¹）合理匹配。据我们所知，这是首次在能带模型和跳跃模型的背景下计算化合物1的传输参数，并且两个计算结果都表明本征空穴迁移率高于相应的本征电子迁移率。我们这里的计算结果将有助于进一步探索其他含更高DPP的醌型小分子的潜力。
