Shi Yuhao, Zheng Yingkai, Wang Jialiang, Zhao Ran, Wang Tao, Zhao Changbin, Chang Kuan-Chang, Meng Hong, Wang Xinwei
School of Advanced Materials, Shenzhen Graduate School, Peking University, Shenzhen 518055, China.
School of Electronic and Computer Engineering, Shenzhen Graduate School, Peking University, Shenzhen 518055, China.
Research (Wash D C). 2020 Aug 30;2020:6587102. doi: 10.34133/2020/6587102. eCollection 2020.
Organic field-effect transistors (OFETs) are of the core units in organic electronic circuits, and the performance of OFETs replies critically on the properties of their dielectric layers. Owing to the intrinsic flexibility and natural compatibility with other organic components, organic polymers, such as poly(vinyl alcohol) (PVA), have emerged as highly interesting dielectric materials for OFETs. However, unsatisfactory issues, such as hysteresis, high subthreshold swing, and low effective carrier mobility, still considerably limit the practical applications of the polymer-dielectric OFETs for high-speed, low-voltage flexible organic circuits. This work develops a new approach of using supercritical CO fluid (SCCO) treatment on PVA dielectrics to achieve remarkably high-performance polymer-dielectric OFETs. The SCCO treatment is able to completely eliminate the hysteresis in the transfer characteristics of OFETs, and it can also significantly reduce the device subthreshold slope to 0.25 V/dec and enhance the saturation regime carrier mobility to 30.2 cm V s, of which both the numbers are remarkable for flexible polymer-dielectric OFETs. It is further demonstrated that, coupling with an organic light-emitting diode (OLED), the SCCO-treated OFET is able to function very well under fast switching speed, which indicates that an excellent switching behavior of polymer-dielectric OFETs can be enabled by this SCCO approach. Considering the broad and essential applications of OFETs, we envision that this SCCO technology will have a very broad spectrum of applications for organic electronics, especially for high refresh rate and low-voltage flexible display devices.
有机场效应晶体管（OFET）是有机电子电路的核心元件，OFET的性能严重依赖于其介电层的特性。由于具有固有的柔韧性以及与其他有机组件的天然兼容性，有机聚合物，如聚乙烯醇（PVA），已成为用于OFET的极具吸引力的介电材料。然而，诸如滞后现象、高亚阈值摆幅和低有效载流子迁移率等不尽人意的问题，仍然极大地限制了聚合物介电OFET在高速、低电压柔性有机电路中的实际应用。这项工作开发了一种新方法，即对PVA电介质进行超临界CO₂流体（SCCO）处理，以实现高性能的聚合物介电OFET。SCCO处理能够完全消除OFET转移特性中的滞后现象，还能将器件亚阈值斜率显著降低至0.25 V/dec，并将饱和区载流子迁移率提高到30.2 cm² V⁻¹ s⁻¹，这两个数值对于柔性聚合物介电OFET来说都非常可观。进一步证明，与有机发光二极管（OLED）耦合时，经SCCO处理的OFET在快速开关速度下能够很好地工作，这表明通过这种SCCO方法可以实现聚合物介电OFET出色的开关行为。考虑到OFET广泛而重要的应用，我们设想这种SCCO技术在有机电子领域将有非常广泛的应用，特别是对于高刷新率和低电压柔性显示设备。
