Electronic Structure and Charge Dynamics at the Tri-pyrene Boroxine–Gold Interface

A combined theoretical and experimental study has been carried out to investigate in detail the electronic structure at the boroxine-gold interface. Tripyrene boroxine adsorbs with a flat geometry on Au(111), and the interaction is driven by dispersion forces. Near-edge X-ray absorption measurements, supported by density functional theory calculations, give strong evidence of the presence of interfacial hybrid unoccupied final states while B 1s resonant photoemission spectroscopy is used to identify a super participator decay process after the B 1s core-hole creation. The charge transfer injection mechanism implied by the B 1s core-hole decay process is accounted for by the calculated energy shift of the lowest unoccupied molecular orbital, which, upon B 1s ionization, partially falls below the Fermi level.