A flexible, transparent, and enzyme free sensor based on Ni@AgNW networks for glucose detection

Silver nanowires (AgNWs) are among the most promising materials for transparent conductive electrodes (TCE) owing to their stability and unique optoelectronic properties. However, the fact that they easily oxidize in chemical environments has limited their applications in devices such as electrochemical batteries, supercapacitors, and sensors. In this study, flexible Ni@AgNW/PET was prepared using the electrochemical deposition method. This electrode architecture prevented the delamination of the flexible electrodes during bending tests. Further, the Ni shell structure protected the AgNWs from oxidation and improved the stability of the conductive substrate. The Ni@AgNW/PET electrodes showed good electrochemical stability with a sheet resistance and optical transmittance of 6.8 Ω/sq and 64.1%, respectively. The electrocatalytic anodic currents correlated with the concentration of glucose, which had a detection limit of 40 μM (S/N = 3), a wide range of 0.01–5.0 mM (with a linear correlation coefficient of 0.998), and a high sensitivity of 915 μA mM−1 cm−2. The flexible Ni@AgNW/PET electrodes remained stable after 1000 bending cycles under different shapes. The excellent electrocatalytic performance for glucose showed that Ni@AgNWs/PET is a promising wearable electrode that can be used in glucose detection.