Berlin 2015 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 90: Sensing, Active Structures and other Applications
O 90.10: Vortrag
Donnerstag, 19. März 2015, 17:15–17:30, MA 144
Bimetallic plasmonic nanosensors: DNA self-assembly and core-shell nanocrystals — •Andreas Tittl1, Na Li2, Domenico Paone1, Song Yue3, Chen Song2, Justus Back4, Sabine Ludwigs4, Baoquan Ding2, Na Liu3, and Harald Giessen1 — 14th Physics Institute and Research Center SCOPE, University of Stuttgart, Germany — 2National Center for Nanoscience and Technology, Beijing, China — 3Max Planck Institute for Intelligent Systems, Stuttgart, Germany — 4IPOC - Functional Polymers, University of Stuttgart, Germany
We present DNA-assembled bimetallic plasmonic nanostructures and demonstrate their application for the all-optical detection of hydrogen. Gold (Au) nanorods are functionalized with DNA strands, which serve both as linkers and seeding sites for the growth of palladium (Pd) nanocrystals and facilitate reliable positioning of Pd satellites around a Au nanorod at an ultrashort spacing in the nanometer range. Dark-field scattering spectra of single Au-DNA-Pd nanorods were recorded during controlled cycles of hydrogen gas exposure, and an unambiguous concentration-dependent optical response was observed. Our method enables, for the first time, the all-optical detection of hydrogen-induced phase-change processes in sub-5 nm Pd nanocrystals at the single-antenna level. By substituting the Pd satellites with other functional materials, our sensor platform can be extended to plasmonic sensing of a multitude of chemical and biological reagents, both in liquid and gaseous phases. Furthermore, we demonstrate core-shell Au-Pd nanocrystals with hydrogen-induced spectral shifts exceeding 100 nm.