High‐Performance Bioelectronic Circuits Integrated on Biodegradable and Compostable Substrates with Fully Printed Mask‐Less Organic Electrochemical Transistors

Abstract

Organic electrochemical transistors (OECTs) rely on volumetric ion‐modulation of the electronic current to provide low‐voltage operation, large signal amplification, enhanced sensing capabilities, and seamless integration with biology. The majority of current OECT technologies require multistep photolithographic microfabrication methods on glass or plastic substrates, which do not provide an ideal path toward ultralow cost ubiquitous and sustainable electronics and bioelectronics. At the same time, the development of advanced bioelectronic circuits combining bio‐detection, amplification, and local processing functionalities urgently demand for OECT technology platforms with a monolithic integration of high‐performance iontronic circuits and sensors. Here, fully printed mask‐less OECTs fabricated on thin‐film biodegradable and compostable substrates are proposed. The dispensing and capillary printing methods are used for depositing both high‐ and low‐viscosity OECT materials. Fully printed OECT unipolar inverter circuits with a gain normalized to the supply voltage as high as 136.6 V−1, and current‐driven sensors for ion detection and real‐time monitoring with a sensitivity of up to 506 mV dec−1, are integrated on biodegradable and compostable substrates. These universal building blocks with the top‐performance ever reported demonstrate the effectiveness of the proposed approach and can open opportunities for next‐generation high‐performance sustainable bioelectronics.

Why PEDOT:PSS Should Not Be Used for Raman Sensing of Redox States (and How It Could Be)

“…Poly­(3,4-ethylenedioxythiophene):poly­(styrene sulfonate) (PEDOT:PSS) is one of the most versatile materials for large-area electronics and bioelectronics with a variety of application in flexible devices, organic solar cells, sensors, thermoelectrics, and organic electrochemical transistors (OECTs). , In addition, recently developed strategies improved its biodegradability, making PEDOT:PSS a promising candidate for green electronics. − PEDOT:PSS is a mixture of two ionomers, PEDOT, which is conductive, and PSS, which is insulating and normally added in excess to make PEDOT soluble in water and suitable for processing in thin-film fabrication, as well as for stabilizing its oxidation state. Unlike most of other conductive polymers, pristine PEDOT is p-doped since its synthesis proceeds through the oxidative polymerization of 3,4-ethylenedioxythiophene (EDOT) monomers, achieved by means of the concurrent reduction of Fe 3+ -based salts.…”

Organic Bioelectronics Development in Italy: A Review

“…From a technological point of view, fabrication techniques derived from silicon technology are exploited [ 39 , 57 , 63 , 64 , 65 , 66 ], as well as 2D and 3D printing technologies [ 7 , 54 , 67 , 68 , 69 , 70 , 71 ]. Moreover, increasingly accurate models have been developed in order to better understand the physical mechanisms governing the device operations, both in terms of the electrolyte-gating working mechanisms and in terms of the biosensor’s response to a given analyte [ 55 , 56 , 59 , 72 ].…”

“…More recently, in 2022, Granelli et al realized a fully printed OECT-based bioelectronic circuit on diacetate cellulose thin film, a compostable substrate [ 7 ]. The fabrication combined dispensing and direct writing methods for the deposition and patterning of the different parts of the transistors, avoiding material waste and resulting in a complete environmentally friendly process.…”

“…Different and significant works came also from Italian academics, particularly in the development of innovative devices; here are a few notable examples: at the University of Brescia and University of Bari, researchers have been involved in the development of innovative devices on biodegradable and compostable substrates [ 7 ] or in the use of green materials and technologies for bioelectronics [ 8 ]. At the University of Modena and Reggio Emilia and University of Ferrara, researchers have focused on developing new materials and techniques for neuromorphic devices for label-free dopamine detection [ 9 ] and for in vivo electrophysiological signal studies [ 10 ].…”

Why PEDOT:PSS Should Not Be Used for Raman Sensing of Redox States (and How It Could Be)

“…5,6 In addition, recently-developed strategies improved its biodegradability, making PEDOT:PSS a promising candidate for green electronics. [7][8][9] PEDOT:PSS is a mixture of two ionomers, PEDOT, which is conductive, and PSS, which is insulating and normally added in excess to make PEDOT soluble in water and suitable for processing in thin-film fabrication, as well as for stabilizing its oxidation state. Unlike most of other conductive polymers, pristine PEDOT is p-doped, since its synthesis proceeds through the oxidative polymerization of 3,4 ethylenedioxythiophene (EDOT) monomers, achieved by means of the concurrent reduction of Fe 3+ -based salts.…”