Conference on Integrated Optics - Devices, Materials, and Technologies XVI, San-Francisco, Costa Rica, 23 - 25 January 2012, vol.8264
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.