Pereira Marcelo Lopes, Sousa Rafael Timóteo, Giozza William Ferreira, Ribeiro Luiz Antonio
Institute of Physics, University of Brasília, Brasília, 70919-970, Brazil.
Department of Electrical Engineering, University of Brasília, Brasília, 70919-970, Brazil.
Sci Rep. 2020 May 6;10(1):7665. doi: 10.1038/s41598-020-63699-w.
Molecular crystals have been used as prototypes for studying the energetic and dynamic properties of charge carriers in organic electronics. The growing interest in oligoacenes and fused-ring oligothiophenes in the last two decades is due, in particular, to the success achieved in conceiving pentacene-based organic photovoltaic devices. In the present work, a one-dimensional Holstein-Peierls model is designed to study the temperature-dependent polaron transport in pentathienoacene (PTA) lattices. The tight-binding Hamiltonian employed here takes into account intra and intermolecular electron-lattice interactions. Results reveal that polarons in PTAs can be stable structures even at high temperatures, about 400 K. During the dynamical process, these charge carriers present a typical 1D random walk diffusive motion with a low activation energy of 13 meV and a room temperature diffusivity constant of 1.07 × 10 cm s. Importantly, these critical values for the polaron diffusion and activation energy are related to the choice of model parameters, which are adopted to describe pristine lattices.
分子晶体已被用作研究有机电子学中电荷载流子的能量和动力学性质的原型。在过去二十年中，对低聚并苯和稠环低聚噻吩的兴趣日益浓厚，尤其归因于基于并五苯的有机光伏器件所取得的成功。在本工作中，设计了一个一维霍斯坦 - 皮尔斯模型来研究五噻吩并苯（PTA）晶格中与温度相关的极化子输运。这里采用的紧束缚哈密顿量考虑了分子内和分子间的电子 - 晶格相互作用。结果表明，即使在约400 K的高温下，PTA中的极化子也可以是稳定结构。在动力学过程中，这些电荷载流子呈现出典型的一维随机游走扩散运动，其活化能低至13 meV，室温扩散常数为1.07×10 cm²/s。重要的是，极化子扩散和活化能的这些临界值与用于描述原始晶格的模型参数选择有关。
