Improving the Performance of pH Sensors With One-Dimensional ZnO Nanostructures

In this study, pH sensors with ZnO nanorods (NRs) or film were fabricated by using a low-cost and simple hydrothermal method. A 100 nm ZnO film was deposited on a glass substrate via radio frequency magnetron sputtering as a seed layer. With the potential method to measure pH value, an AD623 amplifier was used as the readout circuit, and a Pt electrode was used as the reference electrode. The analyte solution included buffer solutions to measure the response potential and repeatability of the sensor at pH 4, 6, 7, 8, and 10. Both ZnO pH sensors exhibited excellent reusability and reproducibility. The sensitivity and linearity of the ZnO NR-based sensor were 44.56 mV/pH and 0.983, respectively, while those of the ZnO film-based sensor were 34.82 mV/pH and 0.992, respectively.