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Spectral Selectivity of Plasmonic Interactions between Individual Up-Converting Nanocrystals and Spherical Gold Nanoparticles

We experimentally demonstrate strong spectral selectivity of plasmonic interaction that occurs between α-NaYF(4):Er(3+)/Yb(3+) nanocrystals, which feature two emission bands, and spherical gold nanoparticles, with plasmon frequency resonant with one of the emission bands. Spatially–resolved luminesc...

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Detalles Bibliográficos
Autores principales: Piątkowski, Dawid, Schmidt, Mikołaj K., Twardowska, Magdalena, Nyk, Marcin, Aizpurua, Javier, Maćkowski, Sebastian
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5578271/
https://www.ncbi.nlm.nih.gov/pubmed/28777315
http://dx.doi.org/10.3390/ma10080905
Descripción
Sumario:We experimentally demonstrate strong spectral selectivity of plasmonic interaction that occurs between α-NaYF(4):Er(3+)/Yb(3+) nanocrystals, which feature two emission bands, and spherical gold nanoparticles, with plasmon frequency resonant with one of the emission bands. Spatially–resolved luminescence intensity maps acquired for individual nanocrystals, together with microsecond luminescence lifetime images, show two qualitatively different effects that result from the coupling between plasmon excitations in metallic nanoparticles and emitting states of the nanocrystals. On the one hand, we observe nanocrystals, whose emission intensity is strongly enhanced for both resonant and non-resonant bands with respect to the plasmon resonance. Importantly, this increase is accompanied with shortening of luminescence decays times. In contrast, a significant number of nanocrystals exhibits almost complete quenching of the emission resonant with the plasmon resonance of gold nanoparticles. Theoretical analysis indicates that such an effect can occur for emitters placed at distances of about 5 nm from gold nanoparticles. While under these conditions, both transitions experience significant increases of the radiative emission rates due to the Purcell effect, the non-radiative energy transfer between resonant bands results in strong quenching, which in that situation nullifies the enhancement.