Ultrasensitive, Inexpensive and Compact Sensing technology

Researchers from King's College London have invented a low cost, compact and versatile technology platform based on electrically-driven plasmonic nanorod metamaterial for a variety of applications including sensing (for gases such as Hydrogen and Oxygen). These can also be used as nanoscale plasmon and light sources as well as nanoreactors.

 

Summary

 

The electron tunnelling in nanoscale metallic junctions is very sensitive to changes in the environment and this effect can be used to monitor the presence of gases. The Researchers from King’s College London have demonstrated the detection of hydrogen and oxygen, two chemicals where there is a big commercial market opportunity. Detecting hydrogen leaks is important in the production of fuel cells and monitoring the presence of oxygen is vital in a wide variety of controlled chemical reactions such as in the manufacture of drugs. This technology can also be designed to detect other molecules as well as different factors such as changes in temperature, and can be used to stimulate chemical reactions which are not normally take place. This type of sensing is highly accurate, low cost, easy to use and provides a visual feedback.

 

Market opportunity

 

The gas sensors market is expected to witness high growth during the forecast period. The overall market is expected to grow from USD 812.3 Million in 2016 to USD 1297.6 Million by 2023, at a CAGR of 6.83% between 2017 and 2023. The base year considered for the study is 2016. Oxygen gas sensors to hold the largest market share in 2023. The rising demand for oxygen gas sensors used in the medical sector in devices, such as anesthesia machines, ventilators, oxygen monitors, and analyzers, is driving the oxygen gas sensors market. Similarly, Hydrogen sensor market is likely to grow significantly over the coming years to detect hydrogen wherever it is produced, stored, distributed or used. (Source: marketsandmarkets.com)

 

IP Status

 

PCT stage

 

Technical Status

 

Proof of principle: Ultra-high sensitivity to Hydrogen and Oxygen has been demonstrated experimentally. 

 

Commercial Status

 

Industry partners are being sought for commercial development of the technology with a view to licensing this technology.

 

Applications

 

-       Gas sensing (for example, Hydrogen and Oxygen)

-       Temperature sensing

-       Stimulated chemical creations for pharmaceutical and other industries

-       Plasmon and light sources for photonic chips

-       Nanoreactors

-       Lab on a chip

 

Advantages

 

- Compact size, portable – 1 cm2 in total size

- Inexpensive, bottom-up fabrication approach

- Optical and electrical detection capabilities for sensing

- Ultrahigh sensitivity of detection – Single molecule level sensitivity

- Simple quantitative read-out –any simple detector can be used to enable quantitative detection

- Versatile sensing – can be designed to transduce a variety of chemical and physical stimuli

- Platform technology with wider applications

 

Sensor Schematic

 

Technology

 

If a bias voltage is applied between two electrodes separated by a nanometer-scale insulating gap, a current can flow between them due to quantum mechanical electron tunnelling. The resulting current depends exponentially on the gap size so that even an atomic-level variation in the gap distance can produce measurable change in the tunnelling current. It depends also on the electronic and structural properties of the medium existed in the gap. Based on this, tunnelling currents are used as a highly sensitive tool for the sensing applications, such as probing molecule binding events in the junctions at the single-molecule level, studying fundamental interfacial processes, or detecting dynamical chemical reactions.

 

In this context, the researchers from King’s College London use a plasmonic metamaterial composed of an array of gold nanorods to construct tunnel junctions, providing one hundred billion tunnel junctions in an area of ~4 mm2. The plasmonic modes in the metamaterial are excited by inelastic tunnelling electrons, which can then decay radiatively into photons visible to the naked eye; meanwhile, the elastically tunnelled electrons appear as highly energetic hot electrons in the nanorod tips, which make the tunnel junctions highly reactive for the activation of chemical reactions. The chemical reactions in the tunnel junctions can in turn modulate in the tunnelling processes, cause dramatic changes in light emission intensity and tunnelling current. This is useful for precise activation of chemical reactions in the tunnel junctions, and the detection of trace gases with compact size and at low cost. Further, the creation of hot elections is very useful to a wide range of industries that are interested in creating new chemicals that do not occur under normal conditions. For example they could be used as nanoreactors to synthesise new molecules in pharma and chemical industries which require high energies. It can also work as a lab-on-a-chip device for developing and understanding new chemical reactions where precise stimulation and monitoring are paramount.

 

Other applications of this technology include temperature sensing, new chemical creation, plasmon and light sources for photonic chips, nanoreactors and lab on a chip.

 

For futher information, please refer to the publication below.

 

Wang, P., Krasavin, A. V., Nasir, M. E., Dickson, W., & Zayats, A. V., Reactive Tunnel Junctions in Electrically Driven Plasmonic Nanorod Metamaterials. Nature Nanotechnol. 13, 159–164 (2018)

 

 

Patent Information:
Category(s):
Physical Sciences
For Information, Contact:
Mugdha Joshi
IP & Licensing Manager
King's College London
mugdha.joshi@kcl.ac.uk
Inventors:
Anatoly Zayats
Wayne Dickson
Pan Wang
Mazhar Nasir
Alexey Krasavin
Keywords: