Analysis of non-ideal effects and electrochemical impedance spectroscopy of arrayed flexible NiO-based pH sensor

Abstract

In this study, nickel oxide (NiO) was used as sensing film of arrayed flexible NiO-based pH sensor, which could reach high sensitivity (63.376 mV/pH) by potentiometric measurement system. Non-ideal effects of the sensor, such as drift and hysteresis effects, were investigated. Drift rate in pH 7 was 3.436 mV/hr, and hysteresis voltages in loops of pH 7 → pH 3 → pH 7 → pH 11 → pH 7 and pH 7 → pH 11 → pH 7 → pH 3 → pH 7 were respectively 4.496 mV and 1.817 mV. Moreover, sensing mechanism was characterized by electrochemical impedance spectroscopy.