Resistive crack-based nanoparticle strain sensors with extreme sensitivity and adjustable gauge factor, made on flexible substrates

In this paper, we report the demonstration of highly sensitive flexible strain sensors formed by a network of metallic nanoparticles (NPs) grown under vacuum on top of a cracked thin alumina film which has been deposited by atomic layer deposition. It is shown that the sensor sensitivity depends on the surface density of NPs as well as on the thickness of alumina thin films that can both be well controlled via the deposition techniques. This method allows reaching a record strain sensitivity value of 2.6 x 10(8) at 7.2% strain, while exhibiting high sensitivity in a large strain range from 0.1% to 7.2%. The demonstration is followed by a discussion enlightening the physical understanding of sensor operation, which enables the tuning of its performance according to the above process parameters.

Automated summary

This paper presents the demonstration of highly sensitive flexible strain sensors formed by a network of metallic nanoparticles grown on top of a cracked thin alumina film. The sensor sensitivity is shown to depend on the surface density of nanoparticles and the thickness of alumina thin films, both of which can be controlled via deposition techniques. The method allows reaching a record strain sensitivity value at 7.2% strain, while exhibiting high sensitivity in a large strain range. The discussion following the demonstration enlightens the physical understanding of sensor operation for tuning its performance according to process parameters.