Nanorods-based sensors

The design and fabrication of novel nanorod-based nanostructures consisting of well-known sensing materials such as ZnO, SnO₂ with new morphology and anisotropy are presented. Ordered arrays consisting of metal oxide building-blocks of controlled morphologies, sizes, and aspect ratios are generated directly onto various substrates from the hydrolysis-condensation and heteronucleation of aqueous metal salts solutions at mild temperatures. Sensor technologies shall be beneficiary of such designed arrays and promising improvements in terms of detection threshold limit and sensitivity, selectivity, response time, and temperature of operation of chemical, gas, and bio-sensors are foreseen with the use of such purpose-built materials. For instance, better sensitivity and selectivity is foreseen due to the optimized architecture such as exposed faces as well as faster response (i.e., lower latency time) due to the direct growth of the nanorod bundles onto various substrates, their perpendicular orientation and their anisotropy along preferential crystal axis, which offers a direct and very efficient electron pathway for amperometric sensors. The synthetic strategy to develop such new anisotropy and well-defined surface morphology and the results obtained on ZnO oriented nanorod-based gas sensors are presented.