Ink-jet printing of graphene for flexible electronics: An environmentally-friendly approach. (December 2015)

• Record Type: Journal Article
• Authors: Capasso, A.; Del Rio Castillo, A.E.; Sun, H.; Ansaldo, A.; Pellegrini, V.; Bonaccorso, F.
• Is Part Of: Solid state communications. Volume 224(2015)
• Page Start: 53
• Page End: 63
• Publication Date: 2015-12
• Subjects: A. Graphene ink -- B. Liquid phase exfoliation -- D. Conductive stripes -- E. PET substrates.; Solid state chemistry -- Periodicals; Solid state physics -- Periodicals; Chimie de l'état solide -- Périodiques; Physique de l'état solide -- Périodiques; 530.41
• DOI: 10.1016/j.ssc.2015.08.011
• Languages: English
• ISSNs: 0038-1098

Abstract

Abstract: Mechanical flexibility is considered an asset in consumer electronics and next-generation electronic systems. Printed and flexible electronic devices could be embedded into clothing or other surfaces at home or office or in many products such as low-cost sensors integrated in transparent and flexible surfaces. In this context inks based on graphene and related two-dimensional materials (2DMs) are gaining increasing attention owing to their exceptional (opto)electronic, electrochemical and mechanical properties. The current limitation relies on the use of solvents, providing stable dispersions of graphene and 2DMs and fitting the proper fluidic requirements for printing, which are in general not environmentally benign, and with high boiling point. Non-toxic and low boiling point solvents do not possess the required rheological properties ( i.e ., surface tension, viscosity and density) for the solution processing of graphene and 2DMs. Such solvents ( e.g ., water, alcohols) require the addition of stabilizing agents such as polymers or surfactants for the dispersion of graphene and 2DMs, which however unavoidably corrupt their properties, thus preventing their use for the target application. Here, we demonstrate a viable strategy to tune the fluidic properties of water/ethanol mixtures (low-boiling point solvents) to first effectively exfoliate graphite and then disperse graphene flakes to formulate graphene-based inks. We demonstrate that such inks can be used to print conductive stripes (sheet resistance of ~13 kΩ/□) on flexible substrates (polyethylene terephthalate), moving a step forward towards the realization of graphene-based printed electronic devices. Highlights: Printing conductive stripes on polyethylene terephthalate (PET) exploiting graphene inks in EtOH/H2 O mixture. Environmentally friendly solvents used to print conductive graphene stripes. High electrical conductivity reached without any pre- or post-processing treatment. Semitransparent stripes with a sheet resistance of 13 KΩ/□ printed on PET.