Empowering Bioelectronics with Supramolecular Nanoarchitectonics: PEDOT-Based Organic Electrochemical Transistors with Tunable Electronic Properties

JOAQUIN DIFORTI; ESTEBAN PICCININI; JUAN ALLEGRETTO; CATALINA VON BILDERLING; WALDEMAR A. MARMISOLLÉ; OMAR AZZARONI

ACS Applied Electronic Materials

American Chemical Society

Año: 2024 vol. 6 p. 1211 - 1222

Organic bioelectronics has the potential to unlock the utmost innovation in medicine and healthcare through thecombination of the biological and digital realms. Particularly, organic electrochemical transistors (OECTs) are apromising class bioelectronics transducer. Nevertheless, a fabrication strategy is needed to lower the access barrierto OECTs, thereby expediting product development and innovation. In this work, we present a supramolecularapproach with simple equipment to prepare conductive films based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), PEDOT:PSS, integrated with cationic molecular blocks for OECTsmanufacturing. By employing the Layer-by-Layer (LbL) self-assembly technique, we facilely prepare transistorchannels of PEDOT:PSS integrated with either the surfactant cetyltrimethylammonium bromide, CTAB, or thepolyelectrolyte poly(diallyldimethylammonium chloride), PDADMAC, with nanometric precision. Both cationic blocksfeature positively charged quaternary amines but possessing different mesogenic and surfactant features. ThePEDOT:PSS/CTAB system yields an electrical conductivity of 275 S m-1, that is 4 orders of magnitude higher than thoseintegrated with PDADMAC (0.0531 S m-1). This enhancement is attributed to CTAB integration, which boostsPEDOT:PSS charge transport, while PDADMAC diminishes it. The electronic performance indicators of OECTs (currentat the on-state, Imax, threshold potential, VTH, transconductance, gm) are easily tuned by adjusting the thickness of thetransistor channel film. The cycling stability of the transistor channel is 8-fold enhanced by coating it with a protectivelayer using non-electroactive polymers. These OECTs exhibit a gm of 2.21 mS, a μC* product (μ is the hole mobility,and C* is the capacitance per unit of volume) of 0.23 F cm−1 V−1 s−1, and on- and off-switching times, 𝝉, of 24.2 and12.3 ms respectively. Their performance was comparable to or better than OECTs with channels prepared usingtechniques based on equipment of higher complexity and cost. Finally, we demonstrate the utility of these facilely prepared OECTs in biosensing the neurotransmitter dopamine with an exceptional sensitivity of 279 mV/decade, andgood operation range (1-300 μM) and reversibility.