Plasmon enhanced luminescence from fullerene molecules excited by local electron tunneling

Tunneling electrons from a scanning tunneling microscope (STM) induce luminescence from C(60) and C(70) molecules forming fullerene nanocrystals grown on ultrathin NaCl films on Au(111). Intramolecular fluorescence and phosphorescence associated with the transitions between the lowest electronic excited state and ground state of C(70) molecules are identified, leading to unambiguous chemical recognition on the nanoscale. Moreover we demonstrate that the molecular luminescence is selectively enhanced by localized surface plasmons in the STM tip-sample gap.