Multifunctional Nanoparticles-Key for Optimizing Chemical Nanosensors

Multifunctional nanoparticles are key for optimizing the performance of chemical sensor devices. We have fabricated a variety of nanosensor devices based on ultrathin metal oxide films and nanowires, which have been integrated on CMOS-based micro-hotplate chips. These sensors have been functionalized with metallic as well as bimetallic nanoparticles. We have demonstrated that Pt-NPs or NiPt-NPs, strongly increase the sensitivity to carbon monoxide and supress the cross selectivity to humidity in case of SnO2 thin film based devices. We have employed both nanoparticles synthesized in solution, which are ink-jet deposited, as well as nanoparticles, which are implemented by gas phase synthesis directly on the micro-hotplate chips. The Pt-functionalized SnO2-thin film sensors show a strongly increased response to CO, which is almost independent of humidity as compared to the bare SnO2-thin film sensor. The highest response of more than 90% has been achieved with NiPt-functionalized SnO2-thin film sensors at a very low operation temperature of only 150°C.