Esmaspäeval, 24. novembril 2014. kell 16.15 toimub Physicumis Ravila 14C 3. korruse seminariruumis D312
Väike materjalifüüsika ja spektroskoopia seminar nr. 186
PhD student , Institute of Physics University of Tartu
Nd3+: KYF4 NANOPARTICLES INTENDED FOR BIOMEDICAL APPLICATIONS: TOWARDS LUMINESCENCE ENHANCEMENT
In the framework of this work we synthesized highly dispersible Nd3+:KYF4 nanoparticles and studied their luminescent properties. The 30-40 nm particles were obtained by means of microwave-hydrothermal technique using a biocompatible poloxamer Emuksol-268 as a surfactant. We study the fluorescence kinetics and the impurity quenching kinetics of the material. We suggest that the main sources of quenching are OH- acceptors located in the volume of the material. We show that the rate of quenching on -OH acceptors is approximately 5 time lower in the material than in the yttrium phosphate nanoparticles doped with neodymium, while the self-quenching and migration rates are approximately 25 times lower, since the radiative lifetime observed for the fluoride nanoparticles is 5 times longer than that for the phosphate nanoparticles. The level of quenching on -OH acceptors is also lower because of lower amount of -OH acceptors. We do not detect significant quenching at the initial ordered stage for the fluoride nanoparticles due to the absence of OH- acceptors in the first coordination sphere of the donor ion. Finally, the dispersibility of the fluoride nanoparticles is higher. This makes the fluoride nanoparticles much more suitable for biomedical applications.