Gas sensing properties of p-type CuBi2O4 porous nanoparticulate thin film prepared by solution process based on metal-organic decomposition

Abstract

Exploring the novel semiconductor-type gas sensors based on complex oxides beyond binary oxides extends the degrees of freedom in chemical sensor research with structural and compositional versatility. In particular, such complex oxides have been reported to exhibit characteristic and promising gas sensing properties, which are mediated by chemical defects. In this work, CuBi2O4 has been prepared in the form of porous nanoparticulate thin film with high surface area-to-volume ratio and small amount of defect (Cu+−oxygen vacancy (VO) complex) by the simple solution process based on metal-organic decomposition (MOD). The film exhibited high gas responses with the specific values of 10.8 toward C2H5OH, 4.2 toward H2, and 2.2 toward CO when measured with 1000 ppm at 400 °C. The particularly high H2S responses (4.7 with 1 ppm, 5.9 with 2 ppm, and 7.4 with 5 ppm) were obtained at 400 °C by the oxidation of H2S on the CuBi2O4 surface. Upon exposure to the oxidizing NO2 gas with low concentrations (≤5 ppm), the resistance of CuBi2O4 thin film sensor was uncommonly increased.