Insulator coated metal nanoparticles with a core/shell geometry exhibit a temperature sensitivity similar to advanced spinels

Chemical Aerosol Engineering as a Novel Tool for Material Science: From Oxides to Salt and Metal Nanoparticles

“…The temperature dependence, given by the negative temperature coefficient was similar or even enhanced when compared to commercial piezoelectric materials (Athanassiou et al 2006). The tunneling based conduction mechanism (Figure 4) showed that core/shell conductive/insulator materials offered a new and simple production route of highly sensitive pressure and temperature sensors (Athanassiou et al 2008;Athanassiou et al 2007b). Luechinger et al (2007) implemented carbon/copper nanoparticles in water based dispersions.…”

Conduction in core/shell nano-composites

“…A temperature dependent conductivity has also been reported in gold nanoparticle/hydrogel composites by Zhao et al 18 where the sample exhibits excellent thermo-switchability. Other mechanisms like activated and non-activated conduction, [19][20][21][22] hopping transport, [23][24][25][26][27] multi-phonon tunneling, 17,24 and Mott metal-insulator transition 28-30 also have been discussed.…”

Advanced Piezoresistance of Extended Metal-Insulator Core-Shell Nanoparticle Assemblies

“…A potential solution around this yet unsolved manufacturing problem comes from the use of large, serial arrays of tunneling barriers where an overall material property would be the combined result of literally millions of tunneling processes. Measuring a distribution of tunneling properties then provides a technically feasible route to use the extreme sensitivity of a barrier for pressure sensing.We have most recently reported on the unexpected high piezoresistance and thermoresistive effect of graphene biand trilayer coated copper nanoparticles [3] and suggested possible explanations based on multielectron tunneling mechanism derived from the temperature dependence of the electrical resistivity [6]. In contrast, multilayer graphene coated (4-6 layers) copper nanoparticles exhibited a much higher conductivity but very weak thermo-or piezoresistance effects.…”

“…We have most recently reported on the unexpected high piezoresistance and thermoresistive effect of graphene biand trilayer coated copper nanoparticles [3] and suggested possible explanations based on multielectron tunneling mechanism derived from the temperature dependence of the electrical resistivity [6]. In contrast, multilayer graphene coated (4-6 layers) copper nanoparticles exhibited a much higher conductivity but very weak thermo-or piezoresistance effects.…”

“…2; 2C 1 =Cu; x À0:78 ]. Even though the absolute conductivity of the two nanocomposites was very different, they exhibit a most similar sensitive negative pressure-coefficient effect of resistance (NPCR [17][18][19]) in contrast to multilayer graphene coated particles from previous studies (4-6 C 1 =Cu; x À0:54 , [6]). …”