August

Picture of the Month - August 2018

Here you see current insights into the research of the LaMa groups. A collection of the former pictures can be found in the Gallery.

Light-induced interaction between a gold nanoparticle and graphene

At first sight, we conducted a rather simple experiment. We put a gold nanoparticle on a graphene sheet and probed the optical response of this hybrid system by scanning a laser beam across it.

However, the Raman scattered light from the graphene probed by the laser yields a surprising amount of information about the microscopic interaction between the gold nanoparticle and its graphene environment in terms of temperature, strain and hot carriers excited by the laser within the gold nanoparticle by plasmonic absorption and transferred into the graphene. By evaluating the frequency of the two most prominent features of graphene’s Raman spectrum, the G- and 2D-Mode, in each spectrum of the 2D-scan and plotting one frequency against the other, we are able to distinguish the three contributions due to their characteristic influence on the frequency of the particular Raman mode.

Such graphene-gold hybrids may be employed in light harvesting and (opto-) electronic devices. The size and shape dependence of the plasmonic properties offers additional degrees of freedom to tune the optical characteristics of such devices.

This picture was submitted by Prof. Dr. Peter J. Klar.