A Chemically-Responsive Nanojunction within a Silver Nanowire

Abstract

The formation of a nanometer-scale chemically responsive junction (CRJ) within a silver nanowire is described. A silver nanowire was first prepared on glass using the lithographically patterned nanowire electrodeposition method. A 1-5 nm gap was formed in this wire by electromigration. Finally, this gap was reconnected by applying a voltage ramp to the nanowire resulting in the formation of a resistive, ohmic CRJ. Exposure of this CRJ-containing nanowire to ammonia (NH(3)) induced a rapid (<30 s) and reversible resistance change that was as large as ΔR/R(0) = (+)138% in 7% NH(3) and observable down to 500 ppm NH(3). Exposure to water vapor produced a weaker resistance increase of ΔR/R(0,H(2)O) = (+)10-15% (for 2.3% water) while nitrogen dioxide (NO(2)) exposure induced a stronger concentration-normalized resistance decrease of ΔR/R(0,NO(2)) = (-)10-15% (for 500 ppm NO(2)). The proposed mechanism of the resistance response for a CRJ, supported by temperature-dependent measurements of the conductivity for CRJs and density functional theory calculations, is that semiconducting p-type Ag(x)O is formed within the CRJ and the binding of molecules to this Ag(x)O modulates its electrical resistance.

Molecular structure, optical, electrical and sensing properties of PANI-based coatings with silver nanoparticles deposited from the active gas phase

“…4) the PANI + AgCl coating has different conductive areas. There are associated with the presence of protonated PANI units [13,33], and the silver nanoparticles with modified interlayer [34,36]. These facts allow us to imagine the equivalent electric circuit of the synthesized composite coating in the form of tandem elements, showed in Fig.…”

“…With the concentration below the percolation threshold, these silver nanoparticles organize the system in which hopping and tunneling transport of charge carriers of all the nanocomposite coating are facilitated. In addition, the nanoparticles form around them the interfacial layer, which also modulates its electrical resistance [8,36].…”

Optical and NH&lt;sub&gt;3&lt;/sub&gt; Gas Sensing Properties of Hole-Transport Layers Based on PEDOT: PSS Incorporated with Nano-TiO&lt;sub&gt;2&lt;/sub&gt;

“…Various nanocomposite films consisting of conducting polymers mixed with carbon nanotubes (CNTs) as an active material have been prepared for application in gas thin film sensors for detecting the adsorption of gas molecules such as CO [11], NH 3 [12] and vapors of organic solvents or water [13] [14]. Xing et al [15] reported that the formation of a nanometer-scale chemically responsive junction (CRJ) within a silver nanowire (AgNW) strongly affected the sensing properties of nanocomposites. The proposed mechanism of the resistance response for a CRJ, supported by temperature-dependent measurements of the conductivity for CRJs and density functional theory calculations, is that semiconducting p-type Ag x O is formed within the CRJ and the binding of molecules to this Ag x O modulates its electrical resistance.…”

Characterization of Humidity Sensing of Polymeric Graphene-Quantum-Dots composites incorporated with silver nanowires

“…However, the best humidity sensitivity () of these sensors reached a value around 11%. Xing et al [15] reported that the formation of a nanometer-scale chemically responsive junction (CRJ) within a silver nanowire (AgNW) strongly affected to sensing properties of nanocomposites. Exposure of the CRJ-containing nanowire to ammonia (NH 3 ) induced a rapid (< 30 s) and reversible resistance change that was as large as ΔR/R 0 = (+) 138% in 7% NH 3 and observable down to 500 ppm NH 3 .…”