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Nanosensor technology based on semiconductor nanocrystals

: Martin, J.; Staudinger, U.; Demir, E.; Spudat, C.; Pötschke, P.; Voit, B.; Otto, T.; Gessner, T.


Broquin, J.E. ; Society of Photo-Optical Instrumentation Engineers -SPIE-, Bellingham/Wash.:
Integrated optics: Devices, materials, and technologies XVI : 23 - 25 January 2012, San Francisco, California, United States
Bellingham, WA: SPIE, 2012 (Proceedings of SPIE 8264)
ISBN: 978-0-8194-8907-4
Paper 82641M
Conference "Integrated Optics - Devices, Materials, and Technologies" <16, 2012, San Francisco/Calif.>
Fraunhofer ENAS ()

We present a new concept of material integrated sensor technology for detection, storage and visualization of mechanical stress and load conditions. Key feature is a double layer consisting of a piezoelectric layer and a semiconductor nanocrystal polymer composite film. Electrical charges are generated within the piezo layer by application of a mechanical load to the structure. The charges are transferred to the composite film and injected into the nanocrystals, causing non-radiative exciton recombination. This results in photoluminescence quenching, which can be detected as local optical contrast. The photoluminescence of CdSe/ZnS core/shell quantum dots has been switched off by application of external voltages smaller than 20 V. It was possible to store the charges in the QDs, and hence the off-state, for several hours. Optical contrast ratios up to 1:125 have been detected so far.