Researchers from Guangdong Technion − Israel Institute of Technology have developed printable graphene inks with low-surface-tension solvents and mild-temperature post-processing using polypropylene carbonate (PPC).
a, b Illustrations of liquid-phase exfoliation (LPE) of graphene from graphite using PPC as a dispersant aid. c Photograph of graphene/PPC isolated as a powder from the liquid medium after LPE. d Photograph of a graphene ink formulated by redispersing the graphene/PPC powder. e Photograph of graphene micro-supercapacitor (MSC) electrodes deposited on paper with the graphene ink by aerosol jet printing. Image from: Communications Materials
In this work, graphene is produced by liquid-phase exfoliation with PPC, and the exfoliated graphene/PPC is used to generate printable inks. As a dispersant aid, PPC improves graphene exfoliation, dispersion stability, and redispersability in solvents with low surface tensions (<30 mJ m–2), facilitating the formulation of desirable inks for efficient aerosol jet printing on diverse substrates.
Moreover, the low decomposition temperature of PPC eases its thermal removal from printed graphene, allowing high electrical conductivity with a mild post-processing temperature of 220 °C.
Consequently, the graphene inks enable the fabrication of fully-printed graphene micro-supercapacitors on heat-sensitive paper substrates, exhibiting high areal capacitances, cycling stability, and mechanical resilience against bending deformation.
This work presents a promising strategy to produce printable graphene inks to advance printability and extend substrate compatibility for graphene-based printed electronics. While demonstrated here for graphene, this ink formulation strategy based on PPC can likely be generalized to other two-dimensional materials.
