Successive Solution Deposition Research Articles

Materials Design Strategies for Solvent-Resistant Organic Electronics

Design of organic π-conjugated semiconducting materials is an exciting avenue of research that has already found promising applications in a wide variety of fields, ranging from stretchable electronics to bioimaging and theranostics. With favorable optoelectronic and thermomechanical properties, these materials and related devices can provide a complementary alternative to commercial silicon-based electronics. One of the most important features of organic semiconductors is their ability to be solution processed, allowing access to a wide variety of printing and solution deposition techniques inaccessible to silicon. However, the solution processability of these materials also poses challenges for the development of multilayer electronics due to potential problems such as swelling, film deformation and interfacial mixing that can occur upon successive solution deposition. Use of orthogonal (noncompatible) solvents and solvent-free deposition methods have been extensively investigated as solutions to this challenge, although the applicability of these approaches is limited by the chemical properties of the materials used. Another approach to address this problem is to focus on the materials rather than deposition methods. Through rational design, functional groups can be used to create triggered solvent resistance through covalent or dynamic intermolecular bonds. Design strategies include the incorporation of photo- and thermally cleavable functional groups in the materials, or the use of chemical additives/reagents to significantly alter the solubility of π-conjugated materials and afford solvent-resistant thin films. This spotlight article presents recent progress toward solvent-resistant organic materials with an emphasis on their use in electronic applications. Recent and key developments will be discussed from a personal perspective, providing an overview of the different approaches used to achieve solvent-resistant semiconducting materials toward the fabrication of advanced, multilayer organic electronics.

High-resolution inkjet printing of all-polymer transistor circuits.

Direct printing of functional electronic materials may provide a new route to low-cost fabrication of integrated circuits. However, to be useful it must allow continuous manufacturing of all circuit components by successive solution deposition and printing steps in the same environment. We demonstrate direct inkjet printing of complete transistor circuits, including via-hole interconnections based on solution-processed polymer conductors, insulators, and self-organizing semiconductors. We show that the use of substrate surface energy patterning to direct the flow of water-based conducting polymer inkjet droplets enables high-resolution definition of practical channel lengths of 5 micrometers. High mobilities of 0.02 square centimeters per volt second and on-off current switching ratios of 10(5) were achieved.