Optimization of Cross-Linked Polyvinyl Alcohol Dielectrics for High-Performance Ultraflexible Organic Field-Effect Transistors

Cross-linking polymer gate dielectric is an efficient strategy to improve its intrinsic properties for high-performance flexible organic field-effect transistors (OFETs). However, the detail optimization process of the polymer films with the various cross-linking degrees is often ignored, which can bring a significant effect on the electrical performance of OFETs. In this work, the cross-linked poly (vinylalcohol) (CPVA) is introduced as the gate dielectrics for the high-performance ultraflexible OFETs. The dielectric property and the surface property of CPVA thin films with various cross-linking degrees are investigated in detail. The OFETs with a high average mobility of 7.3 cm $^{2}\cdot V^{-1}\cdot s^{-1}$ , a current ON/ OFF ratio of over 10 ⁷ , and a lower density of trap states of $8.7\times10$ ¹¹ eV $^{-1}\cdot cm^{-2}$ are achieved successfully. Moreover, the ultraflexible OFET presents a high mobility of over 5.1 cm $^{2}\cdot V^{-1}\cdot s^{-1}$ even bending around a copper wire with a small radius of $400 ~\mu \text{m}$ , due to the ultrathin thickness of the device. These results demonstrate that the CPVA thin film is a promising candidate dielectric material for flexible organic transistors, presenting huge potential for the next-generation flexible electronic devices.