Charge transfer at the α-RuCl³/MnPc interface

The interface of manganese(II) phtalocyanine (MnPc) with an α-RuCl₃ single crystal is studied by means of photoelectron spectroscopy. The organic molecule was evaporated on top of an in situ cleaved α-RuCl₃ bulk crystal in steps. The work function and electron affinity of α-RuCl₃ is determined to be 6.3 and 5.4 eV, respectively, in line with common fluorinated acceptor molecules, but with the potential to absorb more electrons per area at interfaces with other materials. These favorable electronic properties lead to a charge transfer from MnPc to α-RuCl₃ which manifests itself mainly in peak shape changes of core level photoemission spectra and further filling of Ru 4d states as revealed by valence band photoemission. This work demonstrates the promising potential of α-RuCl₃ as a strong acceptor material for interfaces in general, and for organic molecules in particular.