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Highly sensitive sensor layer: nanoNi@C


Abstract

In many areas of industry as well as in daily life modern sensor technology becomes increasingly important. Today’s electrically resistive sensors reach their physical limits due to the inherent sensitivity of the utilized active sensor materials. In particular, two characteristics are crucial: the strain sensitivity (k-factor kappa), which represents the ratio between the resistance change and the relative change in length and, secondly, the temperature range in which the resistance does not depend on the temperature. Typically, metal layers made of nickel-chrome or constantan with kappa approx 2 are used.


Background

In many areas of industry as well as in daily life modern sensor technology becomes increasingly important. Today’s electrically resistive sensors reach their physical limits due to the inherent sensitivity of the utilized active sensor materials. In particular, two characteristics are crucial: the strain sensitivity (k-factor kappa), which represents the ratio between the resistance change and the relative change in length and, secondly, the temperature range in which the resistance does not depend on the temperature. Typically, metal layers made of nickel-chrome or constantan with kappa approx 2 are used.


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Solution

Scientists of the Saarland University of Applied Sciences have now been able to produce a special nanostructured layer that combines both high strain sensitivity and temperature independence of the electrical resistance. The resistive layer nanoNi@C consists of a carbon matrix with clusters of nickel atoms which are enclosed by one or more graphene layers. Electron microscope images show that the individual metal clusters are isolated in the matrix, i.e., they do not touch each other. Therefore, the electric transport is strongly affected by the carbon shell. If a strain or distortion is induced e.g. by outer pressure, this heavily changes the electric transport through the material and consequently the resistance. Regarding the response to strain the new material is more than ten times as sensitive as the conventional metallic DMS materials that are currently available. Apart from that, the sensor layer nanoNI@C is mechanically robust and inert against many materials like fuel and oil. Since the temperature coefficient of resistance (TCR) can be adjusted over a certain range, this material can also be used for the production of high precision resistors.


Advantages

  • Strong resistance change depending on the strain of the material with a k-factor of up to kappa approx 25
  • Temperature-independent resistivity (confirmed experimentally in the range of 100 - 500 K, TCR less than ± 30 ppm/K)

Scope of application

All kinds of sensors for the registration of power/force:

  • Pressure sensors, force sensors, strain gauges
  • Pressure sensors without membrane for high or dynamic pressure
  • High precision resistors with linear temperature dependence

Service

We are looking for production and distribution partners who are interested in purchasing a license. We are looking forward to providing you with further information.


Universität des Saarlandes Wissens- und Technologietransfer GmbH

Dr. Frank Döbrich
0681 302-3508
frank.doebrich@uni-saarland.de
www.wut-uni-saarland.de
Address
Universität des Saarlandes Wissens- und Technologietransfer GmbH Starterzentrum | Gebäude A1 1
66123 Saarbrücken



Development status

Prototype


Patent situation

  • DE 102009011353 pending
  • PCT /EP2009/002530 pending
  • EP 09735811 pending
  • US 12736573 pending

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