The need of effective portable chemical detectors and deployment of remote sensing platforms is continuously growing either for civil, industrial and security applications. In particular, improved detection and diagnosis of CBRN substances, continuous supervision and control of critical infrastructures and environmental security issues (e.g. diagnosis of freshwater, air and soil contamination) are some of the key priority areas for innovative chemical sensor technology development.
Modern distributed sensing platforms, such as Wireless Sensor Network (WSN) or Unmanned Aerial Vehicles (UAVs), require novel sensors that combine high detection performance to miniaturization, low cost, low energy consumption and high operation efficiency.
Nanotechnology opens the possibility of leveraging fundamental mechanisms at the nanoscale in order to control all the basic properties (structural, chemical, electronic, and optical) of a microsystem. This enables today the development of innovative chemical sensors with enhanced sensing capabilities, improved selectivity and sensitivity, and higher reliability.
One-dimensional Metal Oxide (MOX) nano-structures exhibit excellent chemical and thermal stability, as well as very high specific surface area which enhances their sensitivity to chemical molecules. Conductometric devices based on MOX semiconductors are well known and particularly suited for chemical detection in vapour phase with detection limits down to ppb level; however, they often lack of selectivity.
The main goal of AMOXES project to prepare an innovative electro-optical chemical nano-sensor, never tried so far, that combines two different transduction principles on a single device: i) one conventional conductometric MOX sensor and ii) an optical sensor based on Localized Surface Plasmon Resonance (LSPR) effect excited in the MOX nanostructures.
LSPR chemical detection rely on the ability of metallic nanoparticles (such as Au, Ag and Cu), deposited on the MOX surface, to concentrate a specific incident light into subwavelength volumes producing greatly enhanced electromagnetic fields at the surface of the resonant structure. This is used to probe minute changes in the environmental refractive index induced by the presence of toxic and harmful analytes.
Such a novel combination will bring to the enhancement of selectivity – through the cross-sensitivity of the individual transduction mechanisms – and also to an improvement of the overall detection limit. Moreover, the ability of these new sensors to reliably work in different conditions, such as liquid and air, makes them relevant for development of interoperable chemical devices, which may be used in several different NATO operational contexts. The ability of this platform to detect harmful chemicals or anomalies with respect to regular conditions will be tested in a simulated environment.
AMOXES proposal is driven by security issues. Low-power consumption sensors will in turn allow to reduce the size of batteries and increase the autonomy of WSN and UAV systems to ensure wider monitoring capabilities. Electro-optical sensors will also allow for faster response time, down to few milliseconds (ms), which grants higher measurement accuracy and superior reliability. The combination of two transduction effects will enhance the sensor selectivity and reduce at the same time the number of false alarms, which is of critical importance. Thus, empowered sensing platforms shall help by delivering critical information rapidly and dependably to the right point at the right time, thereby significantly improving the efficiency of NATO operations.
The project shall also contribute to boost significantly the competitiveness of innovative European SMEs, like NASYS, working in the rapidly growing global sensor market that is expected to rise to 283,4B USD in 2023.
The consortium brings together partners with well-documented expertise, chosen on grounds of their suitability for the project requirements. UNIBS-SENSOR has made pioneering works in the field of 1D-MOX nanostructures for chemical sensing. TUM will bring in major expertize in technology that allows to synthesize at large-scale, cost-effective, and low temperatures, ZnO and SnO2 nanostructures. ANU has strong expertize in the multi-scale engineering of electronic nanomaterials with emphasis on development of LSPR chemical nanodevices.