Performance of water-based printed hybrid graphene/silver nanoparticles conductive inks for flexible strain sensor applications

Abstract Flexible electronic devices such as wearable strain sensors have drawn a lot of interest in health monitoring systems. In the present study, hybrid ink printed flexible strain sensors made of graphene and silver nanoparticles (AgNPs) was formulated. The main aim of the study is to investigate effect of hybrid graphene and AgNPs ratios on the properties of conductive inks and their performance as flexible strain sensors. The new conductive inks were printed on various types flexible substrates; polyethylene terephthalate (PET), polyimide (PI), and polyvinyl alcohol (PVA). The performance of conductive ink on these substrates were evaluated. Results showed that ratio of graphene/AgNPs influence the properties of conductive inks. Graphene/AgNPs with a 0.3/0.2 wt% exhibit higher stability, wettability, and electrical conductivity than those 0.4/0.1, 0.2/0.3, and 0.1/0.4 wt%. Hybrid Graphene/AgNPs conductive ink printed on PI substrate showed better wettability and electrical performance compared to those on PET and PVA substrates. The gauge factor (GF) of PI substrate is higher 6.2% and 32% compared to PET and PVA at the 30% strain range, respectively. In short, the hybrid graphene/AgNPs strain sensor on PI that showed good linearity, sensitivity, and stability has a high potential to be used in low-strain health monitoring systems.