Nanooptics of molecular-shunted plasmonic nanojunctions.
Gold nanoparticles are separated above a planar gold film by 1.1 nm thick self-assembled molecular monolayers of different conductivities. Incremental replacement of the nonconductive molecules with a chemically equivalent conductive version differing by only one atom produces a strong 50 nm blue-shift of the coupled plasmon. With modeling this gives a conductance of 0.17G(0) per biphenyl-4,4'-dithiol molecule and a total conductance across the plasmonic junction of 30G(0). Our approach provides a reliable tool quantifying the number of molecules in each plasmonic hotspot, here <200.
Engineering and Physical Sciences Research Council (EP/K028510/1)
Engineering and Physical Sciences Research Council (EP/L027151/1)
European Research Council (320503)
Engineering and Physical Sciences Research Council (EP/H007024/1)