3D-Printed Nanoscale-Thick Silver Thin Films for Electrochemical Sensing

Nanoscale-thick silver thin films (Ag-NTF) on indium tin oxide-coated glasses are fabricated at different deposition potentials (1.0-5.0 V) using an electrochemical three-dimensional (3D) printing process. The printing process is carried out using a nozzle with a diameter of 0.25 mm and a printing speed of 1.0 mm s-1. The X-ray diffraction (XRD) data showed that the mean crystallite size of Ag is 17 nm. The optical and field emission scanning electron microscopy (FESEM) data revealed the uniform NTF nature of the Ag-NTF electrode. Transmission electron microscopy (TEM) data showed that Ag-NTF electrode particles have a spherical shape with an average size of 21 nm. Furthermore, electrochemical surface activity study showed that samples deposited at 3.0 V have the best electrochemical activity, and hence, the same are used to develop hydrogen peroxide sensors. The sensing measurements are done using a 0.1 M phosphate buffer saline (PBS) electrolyte. The sensitivity of the Ag-NTF comes out to be 25 +/- 1 mu A mM-1 cm-2 with a lower detection limit (LOD) of 1.0 mu M. The selectivity of the electrode is tested using various interfering chemicals. The developed sensors showed excellent selectivity toward H2O2. Finally, the applicability of the Ag-NTF electrodes toward real-life samples is shown using bovine albumin serum (BSA) and rainwater. For the first time, this study has demonstrated the use of an electrochemical 3D printing process to fabricate electrodes for H2O2 sensing. The inherent nature of the process has the capability to eliminate the conventional tedious route to make such electrodes and to provide a one-step and efficient solution.