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Batteryless Chemical Detection

Lawrence Livermore National Laboratory

Contact LLNL About This Technology

Publications:

PDF Document PublicationAdvanced Materials, 2011, 23, 117-121. (1,804 KB)


Technology Marketing Summary

Existing nanosensor technologies employ gas, chemical, and biological detection methods that depend on an external power source (typically a battery) to operate. This limits conventional technologies by constraining both the nanosensor size, and reachable locations. Lawrence Livermore National Laboratory has developed a superior alternative: the first batteryless sensors using one-dimensional semiconducting nanowires. The commercial applications for this technology include readily deployable chemical sensors for military, industrial, and environmental applications. By freeing the nanosensor from a tethered power supply, LLNL scientists have provided the new standard for portable chemical detectors.

Description

Chemical and biological sensors based on nanowire or nanotube technologies exhibit observable ultrasensitive detection limits due to their unusually large surface-to-volume architecture. This suggests that nanosensors can provide a distinct advantage over conventional designs. This advantage is further enhanced when the nanosensor can harvest its meager power requirements from the surrounding environment. A self-powering or “batteryless” device can made small enough to serve in unique situations ranging from military to medical applications. LLNL researchers successfully fabricated two prototype platforms for batteryless chemical detectors using one-dimensional semiconductor nanowires.

Both ZnO and boron-doped Si nanowires have proved to be excellent sensor materials. The two sensing platforms were therefore based on these two materials. The working principle of both nanosensors relies on the partial exposure of semiconducting nanowires to target chemical species and a non-ohmic contact that is necessary for the nanosensors to function.   

For the first platform, a vertically-aligned ZnO nanowire forest was grown on a support substrate. The nanowire array was infiltrated with PVC polymer and then oxygen plasma etched to expose the tips of the nanowires. These tips were then exposed to various chemical species to observe the change in electrical potential each species induced. Platform two consisted of randomly-aligned Si nanowires. Approximately 50% of that network was then sealed with insulation glue, leaving 30% of the nanowires available to interact with the various chemical species. In each case, the potential difference between the exposed and unexposed nanowires was measured.  For both platforms, de-ionized water produced little electrical signal, while more than 15 types of organic solvents, such as ethanol, etc., generated distinctly different results. The nanosensors detected various chemical species and their concentration levels.

Watch a movie about the batteryless sensor and nanoenergy harvester.

Benefits
  • External power source (such as a battery) is eliminated, reducing bulk
  • Nanosensor responds selectively to a variety of organic molecules
  • Freedom from thermodynamic equilibrium variables yields response times faster than 1 second
  • Heat from the surrounding environment can be used to power the detector
Applications and Industries
  • Potential biological applications, by exploiting the tangible dipole moment found in most organic molecules present in living systems  
  • Counterterrorism contraband sensor programs
  • Ultrasensitive detection of low-concentration gas leaks (pipeline protection)
  • Military, particularly on the battlefield (chemical and biological weapons)
  • Petroleum refinery 
More Information

Watch a movie about the batteryless sensor and nanoenergy harvester.

Patents and Patent Applications
ID Number
Title and Abstract
Primary Lab
Date
Patent 8,344,597
Patent
8,344,597
Matrix-assisted energy conversion in nanostructured piezoelectric arrays
A nanoconverter is capable of directly generating electricity through a nanostructure embedded in a polymer layer experiencing differential thermal expansion in a stress transfer zone. High surface-to-volume ratio semiconductor nanowires or nanotubes (such as ZnO, silicon, carbon, etc.) are grown either aligned or substantially vertically aligned on a substrate. The resulting nanoforest is then embedded with the polymer layer, which transfers stress to the nanostructures in the stress transfer zone, thereby creating a nanostructure voltage output due to the piezoelectric effect acting on the nanostructure. Electrodes attached at both ends of the nanostructures generate output power at densities of .about.20 nW/cm.sup.2 with heating temperatures of .about.65.degree. C. Nanoconverters arrayed in a series parallel arrangement may be constructed in planar, stacked, or rolled arrays to supply power to nano- and micro-devices without use of external batteries.
Los Alamos National Laboratory 01/01/2013
Issued
Patent 8,778,563
Patent
8,778,563
Nanodevices for generating power from molecules and batteryless sensing
A nanoconverter or nanosensor is disclosed capable of directly generating electricity through physisorption interactions with molecules that are dipole containing organic species in a molecule interaction zone. High surface-to-volume ratio semiconductor nanowires or nanotubes (such as ZnO, silicon, carbon, etc.) are grown either aligned or randomly-aligned on a substrate. Epoxy or other nonconductive polymers are used to seal portions of the nanowires or nanotubes to create molecule noninteraction zones. By correlating certain molecule species to voltages generated, a nanosensor may quickly identify which species is detected. Nanoconverters in a series parallel arrangement may be constructed in planar, stacked, or rolled arrays to supply power to nano- and micro-devices without use of external batteries. In some cases breath, from human or other life forms, contain sufficient molecules to power a nanoconverter. A membrane permeable to certain molecules around the molecule interaction zone increases specific molecule nanosensor selectivity response.
Lawrence Livermore National Laboratory 07/15/2014
Issued
Technology Status
Technology IDDevelopment StageAvailabilityPublishedLast Updated
23911PrototypeAvailable07/26/201107/25/2012

Contact LLNL About This Technology

To: Annemarie Meike<meike1@llnl.gov>