Screen-printed nickel hydroxide electrodes: Semiconducting, electrocatalytic, and electrochromic properties

This work presents a methodology to develop functional metal-oxide based inks for screen-printing. Nickel hydroxide has been grown by co-precipitation on the surface of conducting microparticles using different particle to nickel salt ratios. The resulting particles formed the basis of screen-printing inks, used to print electrodes and test structures. The work describes the characterization of the materials through the different stages of development using a range of techniques including SEM, TEM, electrochemical and spectroscopic techniques. The screen printed electrodes have demonstrated their ability to oxidise water at 0.7–0.8 V vs Ag, making them suitable for electrolyzers. Also, glucose can be directly oxidised at these electrodes below 0.6 V vs Ag, with a detection limit around 65 µM, also pointing to enzyme-less biosensing applications. The electrodes also display electrochromism, with charge efficiencies in the range of 50 cm² C⁻¹. Last, the electrodes present an optical bandgap in the range 4.06–4.15 eV, determined by diffuse reflectance spectroscopy. The approach presented here is extensive to other metal oxides, which opens the range of possible screen-printed semiconductors and catalysts considerably.