Experimental overview for green printed electronics: inks, substrates, and printing techniques

The selection of materials and technologies for green printed electronics design is a fundamental and time-consuming task. This paper represents a rigorous experimental overview in which different printing technologies, ink formulations, and paper-based substrates are examined and analyzed. Three printing techniques are investigated: inkjet printing, screen printing, and direct ink writing. Regarding the inks, formulations based on carbon and silver have been chosen as conductive materials. Initially, the electrical properties of the selected inks have been characterized on a conventional substrate in printed electronics such as polyethylene terephthalate. Later, the printing conditions are optimized for various paper-based substrates, including commercial papers and substrates based on cellulose nanofibers (CNF). CNF are also used as a coating for commercial papers and their influence on the printing quality is evaluated. The substrates are also characterized in terms of morphology, wettability, and thermal stability. This study facilitates the benchmarking tasks for researchers developing new devices and contributes toward the eco-design of flexible green printed electronics.