Development of Flexible Electrochemical Glucose Sensors By Inkjet Printing of Novel Graphene Surfaces

Flexible electrodes have been widely employed in wide range of applications including flexible electronics and sensors, bendable screens, and energy storage and conversion devices ( 1, 2 ). The wide range application of these materials made it essential to develop novel flexible electrodes with low cost, high performance and durability. In the present work, we aimed to develop novel inks formulations to be used in inkjet printing method to fabricate flexible electrodes. For this purpose, we modified the surface of graphene layers with sulfonate (-SO 3 H) groups to achieve more stable ink formulations with higher graphene contents than 0.1 mg/ml which is widely used in the literature ( 3 ). The catalytic activity of SO 3 H-modified graphene was improved significantly by decorating the surface with Pd nanoparticles. Thereafter, the prepared ink formulations were deposited on flexible PET substrate using an inkjet printing method. The surfaces of the fabricated electrodes were characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and atomic force microscopy (AFM) methods. In addition, the electronic properties of the electrodes were determined using 4-probe method as a function of repeated printing steps. After the physical and chemical characterizations, the flexible electrodes were used as electrochemical sensors for the detection of glucose. Our preliminary results indicated that the modification of graphene surface with -SO 3 H and Pd enabled to develop flexible electrochemical glucose sensors with high performance. References: R. P. Tortorich, J. W. Choi, Inkjet Printing of Carbon Nanotubes. Nanomaterials 3 , 453-468 (2013). E. B. Secor, P. L. Prabhumirashi, K. Puntambekar, M. L. Geier, M. C. Hersam, Inkjet Printing of High Conductivity, Flexible Graphene Patterns. Journal of Physical Chemistry Letters 4 , 1347-1351 (2013). S. K. Eshkalak et al. , A review on inkjet printing of CNT composites for smart applications. Applied Materials Today 9 , 372-386 (2017).