In-Situ Strain Gauge: Based on Photoluminescence of Quantum Dots

AbstractDue to that the spectra of CdSe/ZnS core/shell nanocrystals showed a wavelength shift when under external pressures, researches are conducted to design a wavelength shift-based strain or stress gauge. However, the spectrum's shift can only be subtly sensitive when the pressure applied to nanocrystals reaches GPa, which makes the gauge hard to be applied to practice. In this paper, it was found that the photoluminescence(PL) intensity of CdSe/ZnS core/shell quantum dots (QDs)epoxy resin composites changes significantly with strain. Meanwhile, the changes remains stable after 3-5 cycles. We coated the QDs-epoxy resin composites on the surface of metal tensile sample, the PL intensity and strain changes synchronously. In addition, it has been successfully proved that the variation of QDs’ concentrations along with the strain is the main reason for the photoluminescence intensity changing. This research has shown the possibility that this kind of nanocomposite can be designed as a new strain gauge to quantitatively detect stress or strain in-situ by being coated on the structure surface