Gilded nanoparticles for plasmonically enhanced fluorescence in TiO2:Sm3+ sol-gel films
1 Institute of Physics, University of Tartu, Riia 142, Tartu 51014, Estonia
2 V. Lashkaryov Institute of Semiconductor Physics of National Academy of Sciences of Ukraine, Kyiv 03680, Ukraine
3 Institute of Chemistry, University of Tartu, Ravila 14A, Tartu 50411, Estonia
Nanoscale Research Letters 2014, 9:143 doi:10.1186/1556-276X-9-143Published: 25 March 2014
Silica-gold core-shell nanoparticles were used for plasmonic enhancement of rare earth fluorescence in sol-gel-derived TiO2:Sm3+ films. Local enhancement of Sm3+ fluorescence in the vicinity of separate gilded nanoparticles was revealed by a combination of dark field microscopy and fluorescence spectroscopy techniques. An intensity enhancement of Sm3+ fluorescence varies from 2.5 to 10 times depending on the used direct (visible) or indirect (ultraviolet) excitations. Analysis of fluorescence lifetimes suggests that the locally stronger fluorescence occurs because of higher plasmon-coupled direct absorption of exciting light by the Sm3+ ions or due to plasmon-assisted non-radiative energy transfer from the excitons of TiO2 host to the rare earth ions.
78; 78.67.-n; 78.67.Bf