Effect of Au Nanorods on Potential Barrier Modulation in Morphologically Controlled Au@Cu₂O Core–Shell Nanoreactors for Gas Sensor Applications

Abstract

In this work, Au@Cu2O core-shell nanoparticles (NPs) were synthesized by simple solution route and applied for CO sensing applications. Au@Cu2O core-shell NPs were formed by the deposition of 30-60 nm Cu2O shell layer on Au nanorods (NRs) having 10-15 nm width and 40-60 nm length. The morphology of Au@Cu2O core-shell NPs was tuned from brick to spherical shape by tuning the pH of the solution. In the absence of Au NRs, cubelike Cu2O NPs having ∼200 nm diameters were formed. The sensor having Au@Cu2O core-shell layer exhibited higher CO sensitivity compared to bare Cu2O NPs layer. Tuning of morphology of Au@Cu2O core-shell NPs from brick to spherical shape significantly lowered the air resistance. Transition from p- to n-type response was observed for all devices below 150 °C. It was demonstrated that performance of sensor depends not only on the electronic sensitization of Au NRs but also on the morphology of the Au@Cu2O core-shell NPs.

Highly stabilized and rapid sensing acetone sensor based on Au nanoparticle-decorated flower-like ZnO microstructures

“…2 (d (101) = 0.2475 nm). In the particle region, an interlayer spacing of 0.232 nm was obtained, complying with the lattice spacing of (1 1 1) planes of the fcc Au [39]. The average sizes of the Au nanoparticles are about 10-20 nm.…”

“…Generally, the gold plays two important roles in increasing the gas sensing properties. Firstly, because the work function of Au (5.1 eV) is larger than ZnO (3.3 eV), the electrons in ZnO will transfer to Au leading to the Schottky barrier and an addition depletion layer at the interface[39,47]_ENREF_40. The conduction channel of Au decorated flower-like ZnO microstructures is much narrower compared with pure ZnO.…”

Plasmon Modes Induced by Anisotropic Gap Opening in Au@Cu2O Nanorods

“…Compared with spherical or nearly spherical Au cores, Au nanorods can support transverse and longitudinal LSPR modes, offering a better tunability of the LSPR wavelength and higher controllability of the optical response through the polarization state of the excitation light . However, there have been only a few reports on coating Cu 2 O on Au nanorods, most of which have focused on the effects of the refractive index and thickness of the Cu 2 O shell on the plasmon resonance shift. How the morphology and structure of the interface between the Au nanorod core and Cu 2 O shell affect the plasmon resonance has so far remained elusive.…”

Facile Synthesis of Cu/Cu2O Nanoparticles–Graphene Composites for Efficient Detection of NO2 at Room Temperature

“…Some techniques have been developed to enhance the sensing performance, including morphological control, 7-9 heterostructure formation and metal nanoparticles modifying. [10][11][12][13][14] Yang et al found that Cu/Cu x O nanoarchitectures showed e®ective detection to NO x . 10 At the same time, Sonawane et al studied the e®ects of Cu doping on good gas sensing properties.…”