Study on the accuracy of Indium-Tin-Oxide (ITO) nanoparticle sensor based on solvent detection characteristics in water

Abstract

We implemented a sensor to measure the concentration of solvents in water and evaluated the accuracy of the sensor. The sensor’s measurement results were compared using cyclic voltammetry, which measures the chemical potential of the solution. A film was produced using Indium-Tin-Oxide (ITO) nanoparticles. Structural and electrical properties of the film, which are closely related to sensor operating characteristics, were investigated. X-Ray Diffraction (XRD) measurements showed that the ITO nanoparticle size is ~ 35 nm. Hall effect measurements at 300 K showed that the carrier concentration n was 4.2–9.2 × 10¹⁸ cm⁻³ and the mobility μ was 0.13–0.68 cm²/Vs. Hall measurements show that grain boundary scattering is the main factor limiting the mobility of ITO film. The response of the sensor to three representative organic solvents methanol (MeOH), ethanol (EtOH), and isopropyl alcohol (IPA) was evaluated at various concentrations of each substance. The electrochemical potential of the analyte was determined using cyclic voltammetry (CV) measurements, and the sensor response was calculated using a simple model. The measurement results of the ITO sensor and the results obtained using CV measurement were consistent with each other within a maximum offset values of 4.9%.