Solvent-Free Toner Printing of Organic Semiconductor Layer in Flexible Thin-Film Transistors

Abstract

A solvent-free printing process for printed electronics was successfully developed using toner-type patterning of organic semiconductor toner particles and subsequent thin-film formation. These processes use the same principle as that used for laser printing. The organic thin-film transistors were prepared by electrically distributing the charged toner onto a Au electrode on a substrate film followed by thermal lamination. The thermal lamination was effective for obtaining an oriented and crystalline thin film. Toner printing is environmentally friendly compared with other printing technologies because it is solvent free, saves materials, and enables easy recycling. In addition, this technology simultaneously enables both wide-area and high-resolution printing.

Dry Printing of Ag–Ni Conductive Particles Using Toner-Type Printed Electronics

“…Toner particles were distributed on the surface of the carrier particles. The conductive Ag-Ni particles sufficiently adhere to the carrier particle surface, owing to an image force between a charged Ag-Ni particle and carrier particle [34]. The toner and carrier weight ratio in the developer was 1:40.…”

“…Ink-jet printing is an on-demand printing method that is sufficiently developed globally. Electrophotographic printing is another on-demand printing method that uses toner particles instead of inks [33,34]. The conductive toner particles used in our electrophotographic printed electronics are almost entirely bare metal particles that do not include chemical agents in the liquid inks and improve the solubility and viscosity.…”

Organic Sensor Array Distributed in Flexible and Curved Surfaces

“…A proper amount of dioctylbenzothienobenzothiophene (C 8 ‐BTBT) powder with a melting point of 126 °C was transferred onto the substrate, and then another PEN film was placed on it. Details of the sample preparation procedure were the same with our previous works . In the last stage of sample preparation, the planer PEN film was deformed by thermal molding .…”

High-Resolution Printing of Various Electronic Materials by Electrophotography

“…The absence of solvent completely suppressed the exhaustion of volatile organic compounds (VOCs). No VOC emissions are preferred when electronic fabrication is replaced with a direct printing process [84][85][86][87].…”

“…In several studies, we fabricated organic field effect transistors [86,87] and macro-scale electrical circuits [85]. In this study, we fabricated simple elements inside small-scale ICs using various electronic materials such as metals, transparent conductors, carbon materials, oxide semiconductors, organic semiconductors, polymer insulators, and inorganic insulators.…”