CO sensing devices based on indium oxide nanoparticles prepared by laser ablation in water

A simple and effective solution route for synthesizing colloidal indium oxide (In2O3) nanocrystallites, i.e. laser ablation in liquid (LAL), is reported. The morphology and chemical structure of the as-prepared samples were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectra (XPS). The results showed the formation of In2O3 nanoparticles with a bimodal distribution, consisting mainly of particles of small diameters (2–5 nm). Sensor devices prepared by spraying directly the LAL colloidal solutions on interdigitated alumina substrates exhibited good sensing properties for the detection of CO at very low concentrations.