Elucidating the Contributions of Plasmon-Induced Excitons and Hot Carriers to the Photocurrent of Molecular Junctions

Interfacial dephasing of plasmons can take place by several mechanisms. Deterministic control over their relative contributions to interfacial charge transfer is essential for many prospect highly efficient photon-harvesting applications. Here, using transport measurements of plasmon-induced current in molecular junctions, it is experimentally demonstrated that when plasmons with intraband energies are exclusively formed momentum matching constraints limit the contribution of hot carriers to the overall photocurrent to such an extent that near-field molecular exciton creation becomes the dominant dephasing mechanism. The implications of this observation are crucial for the realization of light-controlled coherent transport schemes in nanoscale junctions.