Large-Area Alignment of Tungsten Oxide Nanowires over Flat and Patterned Substrates for Room-Temperature Gas Sensing

Alignment of nanowires over a large area of flat and patterned substrates is a prerequisite to use their collective properties in devices such as gas sensors. In this work, uniform single‐crystalline ultrathin W18O49 nanowires with diameters less than 2 nm and aspect ratios larger than 100 have been synthesized, and, despite their flexibility, assembled into thin films with high orientational order over a macroscopic area by the Langmuir–Blodgett technique. Alignment of the tungsten oxide nanowires was also possible on top of sensor substrates equipped with electrodes. Such sensor devices were found to exhibit outstanding sensitivity to H2 at room temperature. Sensing, down to the wire: A facile solution route provides ultrathin tungsten oxide nanowires (see picture, left) which can be aligned over a large area by the Langmuir–Blodgett technique (middle). The aligned tungsten oxide nanowire thin films exhibit excellent sensitivity to H2 at room temperature (right).