DescriptionSilver nanocrystal arrays of 5 nm diameter Ag nanoparticles surrounded by a shell of dodecanethiol are formed by drop-casting. This gives an ordered system of close-packed spherical nanocrystals that enables a thorough analysis of the electromagnetic inter-particle interactions. The position of the two plasmon resonances observed in these nanocrystals is the result of their collective interaction. This collective interaction leads to a low and a high energy plasmon resonance, excited by the electric field components parallel and perpendicular to the interface, respectively. The magnitude of the plasmon resonance splitting previously observed using a variety of different techniques is also found in ellipsometry spectra. We analyzed that the peak separation in the silver nanocrystal arrays is comparable to the optical response of isolated, non-interacting oblate nanocrystals. The optical deformation of the spherical particles as a result of the interaction can be compared with oblate particles that have a depolarization factor of 0.25 parallel to the interface. The ellipsometry measurement shows a better resemblance between calculation and measurement as compared to polarized reflection measurements. Most likely, this is due to the sensitivity for diffuse scattering of the latter technique.
|Period||28 Mar 2007|
|Event title||DPG Frühjahrstagung 2007 Regensburg: (DPG Spring Meeting)|
|Degree of Recognition||International|