Plasmon Induced Heat Funneling from Au to Cu in the Bimetallic Au@Cu Core-Shell Nanoparticles

The bimetallic nanostructures that mix a plasmonic metal with a transition metal in the form of the core-shell nanoparticles are promising to promote catalytic performance. But it is still unclear how the heat (hot electrons and phonons) transfers on the interface between two metals. We have designed and synthesized Au@Cu bimetallic nanoparticles with Au as core and Cu as shell. By using transient absorption spectroscopy, we find that there are two plasmon induced heat funneling processes from Au core to Cu shell. One is the electron temperature equilibrium (electron heat transfer) with equilibration time of ~560 fs. The other is the lattice temperature equilibrium (lattice heat transfer) with equilibration time of ~13 ps. This plasmon induced heat funneling may be universal in similar bimetallic nanostructures, so our finding could contribute to further understanding the catalytic mechanism of bimetallic plasmonic photothermal catalysis.