Inkjet-Printed Graphene Electrodes on a Plastic Armband for Mobile Electrocardiography

Drop-on-demand inkjet printing has shown great potential for wearable health monitoring applications because of its ability to directly pattern on flexible substrates that can conform to curved surfaces such as the skin. Surface biopotential measurements such as electrocardiography is one such example requiring conductive electrodes that can be attached to skin to record the electrical activity of the heart, otherwise known as an electrocardiogram (ECG). Typical pre-gelled, silver/silver chloride (Ag/AgCl) electrodes; also known as "wet electrodes", are known to cause skin irritations with performance degradation over time, and therefore remain largely non-ideal especially in long-term, mobile heath monitoring scenarios. This paper reports, for the first time, the development of a single, fully inkjet-printed graphene-on-plastic monolithic wearable armband, whose performance was benchmarked against commercial Ag/AgCl electrodes during a 1-hour-long ECG recording with five participants. The inkjet-printed graphene-on-plastic armband displayed excellent ECG reception with a signal-to-noise ratio (SNR) of up to 4.2 dB higher than that of commercial electrodes.