Electrospray-Processed Soluble Acenes toward the Realization of High-Performance Field-Effect Transistors

Functionalized acenes have proven to be promising compounds in the field of molecular electronics because of their unique features in terms of the stability, performance, and ease of processing. The emerging concept of large-area-compatible techniques for flexible electronics has brought about a wide variety of well-established techniques for the deposition of soluble acenes, with spray-coating representing an especially fruitful approach. In the present study, electrostatic spray deposition is proposed as an alternative to the conventional spray-coating processes, toward the realization of high-performance organic field-effect transistors (OFETs), on both rigid and flexible substrates. Particularly, a thorough study on the effect of the solvent and spraying regime on the resulting crystalline film’s morphology is performed. By optimization of the process conditions in terms of control over the size as well as the crystallization scheme of the droplets, desirable morphological features along with high-quality crystal domains are obtained. The fabricated OFETs exhibit excellent electrical characteristics, with high field-effect mobility up to 0.78 cm²/(V s), <i>I</i>_on/<i>I</i>_off >10⁴, and near-zero threshold voltages. Additionally, the good performance of the OFETs realized on plastic substrates gives great potentiality to the proposed method for applications in the challenging field of large-area electronics

Polyelectrolyte Layer-by-Layer Assembly on Organic Electrochemical Transistors

Oppositely charged polyelectrolyte multilayers (PEMs) were built up in a layer-by-layer (LbL) assembly on top of the conducting polymer channel of an organic electrochemical transistor (OECT), aiming to combine the advantages of well-established PEMs with a high performance electronic transducer. The multilayered film is a model system to investigate the impact of biofunctionalization on the operation of OECTs comprising a poly­(3,4-ethylene­dioxythiophene) polystyrene­sulfonate (PEDOT:PSS) film as the electrically active layer. Understanding the mechanism of ion injection into the channel that is in direct contact with charged polymer films provides useful insights for novel biosensing applications such as nucleic acid sensing. Moreover, LbL is demonstrated to be a versatile electrode modification tool enabling tailored surface features in terms of thickness, softness, roughness, and charge. LbL assemblies built up on top of conducting polymers will aid the design of new bioelectronic platforms for drug delivery, tissue engineering, and medical diagnostics