Substrate Effect on Liquid Petroleum Gas Sensors of Cuprous Oxide Thin Films Electrodeposited in Acetate Bath

Abstract

Cuprous oxide thin films were electrodeposited in an acetate bath (∼60 °C) using FTO, ITO, Ti, and Cu substrates to understand their influence on the surface morphology of the films and their wetting nature against Liquid Petroleum gas (LPG). According to spectral response and capacitance-voltage analysis, n-Cu2O films resulted in the electrodeposition bath at pH range of 5.7–6.5. In addition, SEM data revealed the substrate effect on crystal morphologies of Cu2O thin films with unique porous and tetrahedron structures of Cu2O having different grain sizes. XRD analysis gives evidence in support of these grain size variation which emphasized Ti and ITO to have the lowest grain sizes of 24 nm and 30.9 nm respectively. Following the contact angle measurements and their wetting natures, characterized films were subjected to LP gas sensing evaluations in which, proved that deposited n-Cu2O films on FTO, ITO, and Ti can improve gas sensor performances with their moderate wetting behaviors. Under stable sensing conditions, ITO exhibits the most enhanced LPG response, recovery, and stability over time. In comparison, all the experimental results unveiled that substrates do have a major effect, in optimizing interface properties of Cu2O films to achieve better response in many fields of applications.