A Very‐High Frequency Solution‐Processed Organic Field‐Effect Transistor With Improved Voltage‐Normalized Frequency of Transition

ABSTRACT Achieving very‐high (VHF) and ultra‐high frequency (UHF) operation in organic field‐effect transistors (OFETs) would expand their field of application to wireless communication. Such vision remains a major challenge, with OFETs mostly limited to High‐Frequency bandwidth (3 – 30 MHz) due to intrinsic limitations, such as contact resistance and charge mobility, and fabrication‐related parasitism, especially when adopting solution‐based approaches. Here, we report on p‐type OFETs exhibiting a frequency of transition ( f T ) up to 135 MHz at V gs = V ds = −22 V, improving the voltage normalized f T ( f T / V 2 ) for VHF organic transistors with f T > 100 MHz to 0.28 MHz V −2 . The devices were realized through a combination of direct‐writing and solution‐processing techniques employing an air‐stable high‐mobility semiconductor blend based on 2,7‐dioctyl[1] benzothieno[3,2‐ b ][1]benzothiophene (C 8 ‐BTBT) and poly(indaceno‐dithiophene‐ co ‐benzothiadiazole) (C 16 IDT‐BT). Femtosecond‐laser sintering enabled submicron gate overlaps (∼ 0.4 µm), minimizing width‐normalized parasitic gate capacitances ( C g /W ≈ 2.5 pF cm −1 ). DC and AC device characteristics can be approximated using compact models, and theoretical simulations indicate that these OFETs could be potentially used to fabricate rectifiers with a ‐3 dB cut‐off frequency of 200 MHz. These results represent a significant step toward high‐speed organic electronics, establishing a pathway for wireless systems fabricated through scalable solution‐based processes.