(38f) Metal/Insulator Core Shell Nanoparticle Assemblies for Sensing Applications

Sensors have become our ?electronic eyes? in virtually any technical process. Simple physical properties such as pressure and temperature have traditionally been monitored by homogeneous, brittle metal oxides (spinels). In our study, we present a completely new solution for the development of low-cost and heterogeneous sensing nanomaterials. In contrast to the currently applied materials, we have found that large arrays of core/shell nanoparticles rapidly change their electrical conductivity with altered pressure or temperature. These metamaterials are composed of a highly conductive metal nano-core covered by ultra thin carbon or silica insulating layers. An electrical current through the sensor has to tunnel through the insulating barrier shell. Since the quantum phenomenon tunneling is highly sensitive, the here described array of core/shell nanoparticles offer a technically feasible solution to using a most fundamental physical principle in an every day application. The sensitivity can be engineered by the system's architecture and the insulating properties of the shell. The flexibility and the easy access to such nanoparticle assemblies suggest applications as new sensitive piezo- and thermoresistive sensors.