The effect of magnesium added at C60/Rubrene heterointerfaces

This study examines the effect of adding magnesium (Mg) at C60/rubrene heterointerfaces by using synchrotron-radiation photoemission spectroscopy. The heterointerface was obtained by depositing C60 on a 4-Å Mg/rubrene surface. The photoemission spectra showed that the added Mg preferentially interacts with and transfers negative charges to C60. The interfacial dipole potential was significantly enlarged, as was the separation between the lowest unoccupied molecular orbital of C60 and the highest occupied molecular orbital of rubrene. The results demonstrate that the addition of Mg should be an effective method for improving the efficiency of light- and current-generating devices.