Esmaspäeval, 15. detsembril 2014. kell 16.15 toimub Physicumis Ravila 14C 3. korruse seminariruumis D312
Väike materjalifüüsika ja spektroskoopia seminar nr. 188
Kerda Keevend1, Ekaterina Rostova2, Alexander Vanetsev1, Ilmo Sildos1, Sergei Sekatskii2, Yurii Orlovskii1
1Institute of Physics, University of Tartu, 2Swiss Federal Insititute of Technology Lausanne
Study of luminescent dielectric nanoparticles and their nanocomposites with AFM and SNOM for fluorescent quantum yield enhancement
The current talk is based on the results obtained from the collaboration between Laser Spectroscopy Laboratory and Laboratory of Physics of Living Matter in Swiss Federal Insititute of Technology Lausanne (EPFL). The water dispersible luminescent KYF4 nanoparticles doped with Nd3+ and Er3+ are synthesized using microwave hydrothermal tehnique in presence of a biocompatible poloxamer Emuksol-268 as a surfactant. Nanocrystals are spin coated on a glass substrate using three different techniques in order to get single nanocrystals and study their properties with AFM and SNOM.
In future we intend to study the dependence of the fluorescence quantum yield of the RE ions electronic levels strongly quenched by multiphonon relaxation versus the distance between emitting object and gold tip. This task implies of moving the tip in the range of 5 - 50 nm relatively to the ultrathin layer of fluoride nanoparticles doped with trivalent rare-earth ions (Nd, Er). An enhancement of fluorescence quantum yield at the proper distance between the tip and the sample due to plasmonic resonance is expected.