Surface Plasmon Coupling of Compositionally Heterogeneous Core–Satellite Nanoassemblies

• Published in: The journal of physical chemistry letters Vol. 4; no. 9; pp. 1371 - 1378
• Main Authors: Yoon, Jun Hee, Zhou, Yong, Blaber, Martin G, Schatz, George C, Yoon, Sangwoon
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 02.05.2013
• Subjects: Plasmonics, Optical Materials, and Hard Matter; heterogeneous nanoassembly; surface plasmon coupling; charge transfer plasmon; generalized multiparticle Mie theory; core−satellite nanoassembly; hybridization of surface plasmon mode
• ISSN: 1948-7185; 1948-7185
• DOI: 10.1021/jz400602f

Understanding plasmon coupling between compositionally heterogeneous nanoparticles in close proximity is intriguing and fundamentally important because of the energy mismatch between the localized surface plasmons of the associated nanoparticles and interactions beyond classical electrodynamics. In this Letter, we explore surface plasmon coupling between silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs), assembled in the form of core–satellite structures. A recently developed assembly method allows us to prepare ultrapure core–satellite nanoassemblies in solution, where 50 nm AgNPs are surrounded by 13 nm AuNPs via alkanedithiol linkers. We observe changes in the plasmon coupling between the AgNP core and AuNP satellites as the core-to-satellite gap distance varies from 2.3 to 0.7 nm. Comparison with theoretical studies reveals that the traditional hybridized plasmon modes are abruptly replaced by charge-transfer plasmons at a ∼1 nm gap. Changes with the number of satellites are also discussed.