A project between Swedish company Insplorion and innovation consultancy RISE Acreo has found potential to build low cost nanosensors in large volume production for applications like battery monitoring.
Their preliminary study, “Miniaturization of a nanosensor system for batteries,” verifies that it is possible to build very cheap fiber optic sensor systems that meet the requirements of battery sensing applications as well as others, such as in-vivo diagnostics and process industries. The study was carried out based on Insplorion’s nanoplasmonic sensing (NPS) technology, which exploits a physical phenomenon called localized surface plasmon resonance (LSPR).
The purpose of the study was to investigate the possibility of designing a fiber optic sensor system based on NPS for large-scale production at low cost.
“The key conclusions from the project are that it has been confirmed and clarified that we can use volume components that enable a competitive manufacturing price and how it will scale in manufacturing with larger volumes,” said Patrik Dahlqvist, Insplorion’s CEO. “We can build cheap sensor systems for a first series of batteries for niche applications. However, some technical development and verification are necessary to build the sensor systems that can reach the broad market.”
The LSPR technology is a coherent, collective spatial oscillation of the conduction electrons in a metallic nanoparticle, which can be directly excited by near-visible light. The resonance condition (i.e. the wavelength/color of light which can excite the LSPR) is defined by a combination of the electronic properties of the nanoparticles, their size, shape and temperature, and the dielectric environment in close proximity of the nanoparticles.
Nanoplasmonic sensing exploits metallic nanoparticles, usually silver or gold, as local sensing elements, which offer a combination of unique properties; including ultrahigh sensitivity, small sample amount/volume (due to nanoparticle dimensions of the sensor, typically in the 50 – 100 nm size range), and capability for fast, real-time (millisecond time resolution) remote readout.
In Insplorion’s patent-pending nanoplasmonic sensing (NPS) chip architecture, the sensing is realized through nanofabricated arrays of non-interacting, identical gold nanodisks on a transparent substrate. This gold nanodisk array (the sensor) is then covered with a thin (few tens of nm) film of a dielectric spacer layer (see figure) onto which a sample material (e.g. nanoparticles or a thin film) is deposited. The sensor nanoparticles are thereby embedded in the sensor surface and not physically interacting with the studied nanomaterial, except via the LSPR dipole field. The latter penetrates though the spacer layer and has considerable strength on and in proximity to its surface and can, therefore, sense dielectric changes there.