Low-Temperature, Sustainable Manufacturing of Printed OTFT Backplanes for Electrophoretic and OLED Displays

Printed electronics have garnered significant attention for developing lightweight, cost-effective, and environmentally friendly systems, driving significant advancements in the realm of sustainable electronics. This study introduces a printed active-matrix organic thin-film transistor (OTFT) backplane, fabricated under ambient conditions using low-temperature printing and solution-based processes. All electrode layers-including gate, source/drain, and pixel electrodes-are patterned through reverse-offset printing (ROP), achieving high-resolution multilayer integration with minimum line widths of 10 µm. The resulting OTFTs demonstrate robust performance in ambient air, achieving a carrier mobility of 1.12 cm² Vs^-1 and on/off ratios exceeding 10⁸. The printed backplane is integrated with an electrophoretic display panel, enabling stable black-and-white image rendering through pixel-level addressing. The same printing technology is employed to fabricate and drive an organic light-emitting diode (OLED) display, utilizing white OLEDs with laminated color filters. X-ray photoelectron spectroscopy validates that residual polydimethylsiloxane (PDMS) contamination from the ROP process can be eliminated through IPA rinsing, ensuring clean electrode surfaces. The fabrication process is conducted at temperatures exceeding 160 °C without vacuum equipment, significantly reducing energy consumption and material waste. This environmentally sustainable approach can be employed to develop future flexible and disposable electronics. The versatility of printed backplanes demonstrated here highlights their potential to drive next-generation, environmentally friendly display technologies.