We demonstrate rectification ratios (RR) of ≳1000 at biases of 1.3 V in bilayers of C60 deposited on copper. Using scanning tunneling spectroscopy and first-principles calculations, we show that the strong coupling between C60 and the Cu(111) surface leads to the metallization of the bottom C60 layer, while the molecular orbitals of the top C60 are essentially unaffected. Due to this substrate-induced symmetry breaking and to a tunneling transport mechanism, the system behaves as a hole-blocking layer, with a spatial dependence of the onset voltage on intra-layer coordination. Together with previous observations of strong electron-blocking character of pentacene/C60 bilayers on Cu(111), this work further demonstrates the potential of strongly hybridized, C60-coated electrodes to harness the electrical functionality of molecular components.
|Original language||English (US)|
|Journal||Journal of Chemical Physics|
|State||Published - Mar 7 2017|
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry