Cleanroom‐Free Direct Laser Micropatterning of Polymers for Organic Electrochemical Transistors in Logic Circuits and Glucose Biosensors

• Published in: Advanced science Vol. 11; no. 27; pp. e2307042 - n/a
• Main Authors: Enrico, Alessandro, Buchmann, Sebastian, De Ferrari, Fabio, Lin, Yunfan, Wang, Yazhou, Yue, Wan, Mårtensson, Gustaf, Stemme, Göran, Hamedi, Mahiar Max, Niklaus, Frank, Herland, Anna, Zeglio, Erica
• Format: Journal Article
• Language: English
• Published: Germany John Wiley & Sons, Inc 01.07.2024; John Wiley and Sons Inc; Wiley
• Subjects: 4-ethylenedioxythiophene) polystyrene sulfonate; Ablation; Biosensors; conjugated polymer; direct writing; Electrodes; Electrolytes; Glass substrates; Gold; Lasers; Manufacturing; Medicin och hälsovetenskap; Microscopy; organic electrochemical transistor; poly; poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate; Polymer films; Polymers; Screen printing; Semiconductors; Solvents; Transistors; ultrashort pulsed lasers; Writing; poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate; direct writing; conjugated polymer; ultrashort pulsed lasers; organic electrochemical transistor
• ISSN: 2198-3844; 2198-3844
• DOI: 10.1002/advs.202307042

Organic electrochemical transistors (OECTs) are promising devices for bioelectronics, such as biosensors. However, current cleanroom‐based microfabrication of OECTs hinders fast prototyping and widespread adoption of this technology for low‐volume, low‐cost applications. To address this limitation, a versatile and scalable approach for ultrafast laser microfabrication of OECTs is herein reported, where a femtosecond laser to pattern insulating polymers (such as parylene C or polyimide) is first used, exposing the underlying metal electrodes serving as transistor terminals (source, drain, or gate). After the first patterning step, conducting polymers, such as poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), or semiconducting polymers, are spin‐coated on the device surface. Another femtosecond laser patterning step subsequently defines the active polymer area contributing to the OECT performance by disconnecting the channel and gate from the surrounding spin‐coated film. The effective OECT width can be defined with high resolution (down to 2 µm) in less than a second of exposure. Micropatterning the OECT channel area significantly improved the transistor switching performance in the case of PEDOT:PSS‐based transistors, speeding up the devices by two orders of magnitude. The utility of this OECT manufacturing approach is demonstrated by fabricating complementary logic (inverters) and glucose biosensors, thereby showing its potential to accelerate OECT research. Ultrafast focused femtosecond laser has been introduced for the direct micropatterning of organic electrochemical transistors (OECTs), providing high resolution (2 µm), selective cleanroom‐free patterning of insulating and conjugated polymer layers while preserving device operation, and high flexibility in device design. The approach has been validated in the fabrication of complementary inverters and glucose biosensors.