Thermal -lens study of thermo-optical properties of CdSe/ZnS quantum dots embedded into PMMA matrix

Thermal Lens (TL) and spectroscopic characterizations were performed in CdSe/ZnS core-shell nanoparticles embedded into the underlying polymethyl methacrylate (PMMA) dissolved in chloroform (CHCl3). TL measurements were accomplished in function of the CdSe/ZnS quantum-dot concentration (12-60 mg/ml). The average value obtained for the thermal diffusivity was (0.85 ± 0.02) x 10-3 cm2/s. The absolute nonradiative quantum efficiency φ and the fluorescence quantum efficiency η were determined by the TL method. Higher values of φ were obtained with the increase of the core-shell nanoparticles concentrations in PMMA-chloroform solutions. These results are in agreement with the behavior of fluorescence spectra that decrease with CdSe/ZnS concentration increase.

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