Sun Shih-Jye, Menšík Miroslav, Toman Petr, Chung Cheng-Han, Ganzorig Chimed, Pfleger Jiří
Department of Applied Physics, National University of Kaohsiung, Kaohsiung 811, Taiwan, Republic of China and Department of Physics, National Sun Yat-sen University, Kaohsiung 80424, Taiwan, Republic of China.
Institute of Macromolecular Chemistry, AS CR, v.v.i., Heyrovského nám. 2, 162 06 Prague, Czech Republic.
Phys Chem Chem Phys. 2020 Apr 15;22(15):8096-8108. doi: 10.1039/c9cp06477j.
We present a model of the charge transport in thin film organic field-effect transistors with the active channel made of linear conjugated chains stacked on the substrate with end-on-orientation. The transport was simulated in a box consisting of 25 polymer chains, in which the delocalized quantum orbital eigenstates of the on-chain hole distribution were calculated. The inter-chain charge transfer was solved semi-classically. The full self-consistent distribution of charge density and electric field was determined for various applied gate and source-drain voltages. We found that the dependence of charge mobility on gate voltage is not monotonic: it first increases with increasing gate voltage for a limited interval of the latter, otherwise it decreases with the gate voltage. Next, we found formation of the second resonant peak for higher gate voltages. The mobility dependence on the gate voltage confirmed that the current flowing through the active semiconductor layer should be described not only as the hole transfer between adjacent repeat units of the neighbouring chains, but also as the transfer of coherences among on-chain repeat units. The presented model can also give a new insight into the charge transport in organic field-effect transistors with a novel vertical architecture.
我们提出了一种用于薄膜有机场效应晶体管中电荷传输的模型，其有源沟道由以端对端取向堆叠在基板上的线性共轭链构成。在一个由25条聚合物链组成的盒子中对传输进行了模拟，其中计算了链上空穴分布的离域量子轨道本征态。链间电荷转移采用半经典方法求解。针对各种施加的栅极电压和源漏电压，确定了电荷密度和电场的完全自洽分布。我们发现电荷迁移率对栅极电压的依赖性并非单调：在栅极电压的有限区间内，它首先随栅极电压的增加而增加，否则随栅极电压降低。接下来，我们发现对于更高的栅极电压会形成第二个共振峰。迁移率对栅极电压的依赖性证实，流经有源半导体层的电流不仅应描述为相邻链的相邻重复单元之间的空穴转移，还应描述为链上重复单元之间的相干性转移。所提出的模型还可以为具有新型垂直结构的有机场效应晶体管中的电荷传输提供新的见解。
