Organic Material Lab., Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd , 130 Samsung-ro, Suwon 16678, Gyeonggi, Republic of Korea.
Department of Energy and Materials Engineering, Dongguk University , 30 Pildong-ro 1-gil, Jung-gu, Seoul 04620, Republic of Korea.
ACS Appl Mater Interfaces. 2017 Nov 8;9(44):38728-38736. doi: 10.1021/acsami.7b12974. Epub 2017 Oct 30.
We report a newly synthesized donor (D)-acceptor (A)type semiconducting copolymer, consisting of thiophene as an electron-donating unit and thiazole as an electron-accepting unit (PQTBTz-TT-C8) for the active layer of the organic field-effect transistors (OFETs). Specifically, this study investigates the structure and electrical property relationships of PQTBTz-TT-C8 with comprehensive analyses on the charge-transporting properties corresponding to the spin rate of the spin coater during the formation of the PQTBTz-TT-C8 film. The crystallinity of PQTBTz-TT-C8 films is examined with grazing incidence X-ray diffraction. Temperature-dependent transfer measurements of the OFETs are conducted to extract the density of states (DOS) and characterize the charge-transport properties. Comparative analyses on charge transports within the framework of the physical model, based on polaron hopping and Gaussian DOS, reveal that the prefactors of both physical charge-transport models are independent of the spin-coating condition for the films. For staggered structural transistors, however, the thickness of the PQTBTz-TT-C8 films, which strongly affect the series resistance along the charge-transfer path in a vertical direction, is changed in accordance with the spin-coating rate. In other words, the spin-coating rate of the PQTBTz-TT-C8 films influences the thickness of the polymer films, yet any significant changes in the crystallinity of the film or electronic coupling between the neighboring molecules upon the spin-coating condition were barely noticeable. Because the PQTBTz-TT-C8 backbone chains inside the thin film are stacked up with the edge-on, the series resistances are changed according to the thickness of the film and thus the performance of the device varies depending on the thickness.
我们报告了一种新合成的给体（D）-受体（A）型半导体共聚物，由噻吩作为电子给体单元和噻唑作为电子受体单元组成（PQTBTz-TT-C8），用于有机场效应晶体管（OFET）的活性层。具体来说，本研究通过综合分析在 PQTBTz-TT-C8 薄膜形成过程中旋涂机的旋转速度对电荷输运性质的影响，研究了 PQTBTz-TT-C8 的结构和电性能关系。使用掠入射 X 射线衍射研究了 PQTBTz-TT-C8 薄膜的结晶度。对 OFET 的温度依赖性转移测量进行了分析，以提取态密度（DOS）并表征电荷输运性质。基于极化子跃迁和高斯 DOS 的物理模型，对电荷输运进行了比较分析，结果表明，两种物理电荷输运模型的前因子都与薄膜的旋涂条件无关。然而，对于交错结构晶体管，PQTBTz-TT-C8 薄膜的厚度强烈影响垂直方向上的电荷转移路径中的串联电阻，而厚度会根据旋涂速率而变化。换句话说，PQTBTz-TT-C8 薄膜的旋涂速率会影响聚合物薄膜的厚度，但在旋涂条件下，薄膜的结晶度或相邻分子之间的电子耦合几乎没有明显变化。由于薄膜内部的 PQTBTz-TT-C8 主链以边缘向上的方式堆积，串联电阻会根据薄膜的厚度而变化，因此器件的性能会根据厚度而变化。
