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

Abstract

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 W18 O49 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.

Multiscale Nanoparticle Assembly: From Particulate Precise Manufacturing to Colloidal Processing

“…Such liquid-crystal-like structures were found to exhibit anisotropic photocatalytic properties [69] or good performance for UV light detection. [71] If the nanow-ires have a high aspect ratio combined with a small diameter, then it is particularly challenging to get long-range order, because the structural flexibility induces bending, curling, and entanglement of the nanowires. [16,62] Generally, a dispersion of hydrophobically surface-functionalized nanowires in an organic solvent is spread on the water surface of an LB trough, forming a monolayer of randomly www.afm-journal.de www.advancedsciencenews.com oriented nanowires at the air-water interface (Figure 7b, left).…”

Ultrasensitive NO2 gas sensors using tungsten oxide nanowires with multiple junctions self-assembled on discrete catalyst islands via on-chip fabrication

“…In particular, TONWs are one of the important materials for highly sensitive gas sensors [20,21]. Surprisedly, a very limited work has reported on the on-chip fabrication of TONW gas sensors.…”

Mesoporous WN/WO3-Composite Nanosheets for the Chemiresistive Detection of NO2 at Room Temperature

“…Metal oxide semiconductors (MOSs) based gas sensors have been intensely investigated for their high sensitivity, excellent selectivity, good portability, and low cost [5][6][7]. However, for detecting lower concentrations of toxic and disease signal gases, composite materials have shown greater potential than bare materials which exhibit low or no sensitivity in low gas concentrations (sub-ppm), as well as poor selectivity [8,9]. These composite materials include heterostructural materials, doped materials, and noble metal decorated materials, among which the heterostructural materials have been widely investigated because of super injection of carriers [10,11].…”