Hysteresis-Free, High-Performance Polymer-Dielectric Organic Field-Effect Transistors Enabled by Supercritical Fluid

Abstract

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 CO2 fluid (SCCO2) treatment on PVA dielectrics to achieve remarkably high-performance polymer-dielectric OFETs. The SCCO2 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 cm2 V−1 s−1, 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 SCCO2-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 SCCO2 approach. Considering the broad and essential applications of OFETs, we envision that this SCCO2 technology will have a very broad spectrum of applications for organic electronics, especially for high refresh rate and low-voltage flexible display devices.

Atomic Layer Deposition of Iron, Cobalt, and Nickel Chalcogenides: Progress and Outlook

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Performance Enhancement and Bending Restoration for Flexible Amorphous Indium Gallium Zinc Oxide Thin-Film Transistors by Low-Temperature Supercritical Dehydration Treatment

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Controlling Structural and Energetic Disorder in High-Mobility Polymer Semiconductors via Doping with Nitroaromatics

“…To overcome these challenges, significant efforts have been made to design new polymers (with varied substituents and heteroatoms, donor–acceptor copolymers, improved backbone planarity, etc. ) − to better understand the device physics and to engineer new device architectures and interfaces. − Aligning the polymer backbone chains in the OFET channel direction (nanogrooving, blade coating, etc. ), , postprocessing strategies (thermal and solvent vapor annealing), additives (solvents or ionic additives), , and blending approaches (with insulating or semiconducting materials), to name but a few, have also led to enhanced charge transport properties of polymer OFETs.…”