Esmaspäeval, 11. veebruaril 2019 kell 16.15 toimub Physicumis, W.Ostwaldi 1, seminariruumis D312
Laserspektroskoopia seminar No 267
Esineb Leonid Dolgov , TÜ FI laserspektroskoopia labor
Plasmonic Ag@SiO2 nanoparticles for enhancement of Mg2TiO4:Mn4+ red phosphor
Experience related to 2017-2018 stay and work at the School of Chemistry, Sun Yat Sen University, Guangzhou, China will be reported. Some remarks and comments will be given concerning organization of university and everyday life in China.
Main attention will be paid to preparation and properties of Mg2TiO4:Mn4+ phosphor containing plasmonic silver nanoparticles.
Noble metal nanoparticles working as optical antennas incorporated both into organic and inorganic phosphor materials can increase their excitation and emission efficiencies. However, combination of metal nanoparticles with inorganic crystal phosphors is still a challenge. Preparation route for such materials should be balanced so to provide sufficient crystallization of the host and simultaneously avoid melting, oxidation or agglomeration of nanoparticles. The combination of Ag@SiO2 nanoparticles with prospective Mg2TiO4:Mn4+ red phosphor is prepared here by spare low temperature annealing of sol-gel precursor. Non-monotonous dependence of samples’ luminescence on the size and concentration of nanoparticles with 40 and 70-nm silver cores was investigated. It is shown that quantum yield of Mg2TiO4:Mn4+ phosphor can be up to 1.4 times increased at proper concentration and size of Ag@SiO2 nanoparticles mainly because of better excitation of Mn4+ ions.