Effect of addition of non ionic surfactant on the gas sensing properties of CuO films

Non ionic surfactant (Poly ethylene glycol (PEG-400)) has been used as dispersing and stabilizing agent along with citric acid in the sol-gel reaction to synthesize nanocrystalline CuO structures The decomposed gel sample calcined at temperature of 400°C has been assembled on glass substrate using an organic binder to form thick film sensor. The X-ray diffraction study of samples shows the formation of CuO as dominant phase in as decomposed gel and calcined CuO powder samples. Surfactant addition in precursor results in the decrease of crystallite size and leads to uniform distribution of CuO aggregates as noticed in the SEM micrographs. The activation energy of charge carrier in thick film samples has been investigated by two probe technique and is found to be of the order of 0.24 eV. Gas sening measurements on the samples performed at room temperature for analyte (ammonia gas) show an increase in response (4 times) as compare to sample formed by same procedure without surfactant.