Comparison of Magnesium and Titanium Doping on Material Properties and pH Sensing Performance on Sb2O3 Membranes in Electrolyte-Insulator-Semiconductor Structure

Preparation and application of a Cu-doped antimony electrode to improve the performance of pH measurement in seawater

Antimony-based electrodes are widely used in various fields for pH detection due to their low cost. However, their application in the marine environment is significantly hampered by the significant potential drift observed in seawater pH measurements. This study focuses on enhancing the stability of a pure antimony electrode by doping various amounts of copper without compromising its pH response. A series of electrochemical tests demonstrated that the fabricated alloy electrodes exhibited excellent pH response characteristics, including sensitivity, ion selectivity, response time, reversibility, and temperature coefficients. Moreover, the alloy electrodes were more resistant to corrosion than the pure antimony electrode, thereby guaranteeing the stability. Notably, the alloy electrodes containing 63 at% and 70 at% antimony exhibited superior electrochemical characteristics. The surface analysis elucidated that the alloy electrode had reduced oxidation, surface cracks and antimony peeling compared to the pure antimony electrode. Furthermore, the prepared alloy electrodes exhibited excellent pH response and stability in simulated high-salinity seawater and real seawater. The above results highlight that doping cheap copper into antimony can improve the electrode stability by enhancing the corrosion resistance and slowing down the oxidation rate, thus enabling reliable long-time operation in a relatively stable state. These findings provide experimental support for developing novel pH electrodes based on non-noble metals for use in challenging environments such as seawater.

Influence of Y Doping on WO3 Membranes Applied in Electrolyte-Insulator-Semiconductor Structures

In this paper, tungsten oxide (WO₃) is deposited on a silicon substrate applied in electrolyte-insulator-semiconductor structures for pH sensing devices. To boost the sensing performance, yttrium (Y) is doped into WO₃ membranes, and annealing is incorporated in the fabrication process. To investigate the effects of Y doping and annealing, multiple material characterizations including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atom force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) are performed. Material analysis results indicate that annealing and Y doping can increase crystallinity, suppress defects, and enhance grainization, thereby strengthening membrane sensing capabilities in terms of sensitivity, linearity, and reliability. Because of their stable response, high reliability, and compact size, Y-doped WO₃ membranes are promising for future biomedical applications.