Physical Review Letters · 2005 · 266 citations · 28 references
Natural SciencesChemistryMaterials ScienceInterface ScienceMaterials ChemistrySurface ScienceCharge Transfer ReactionsChemical BondingInterface EngineeringMetal-semiconductor ContactsOrganic Electronic MaterialsOrganic SemiconductorsCarrier Transport In Organic SemiconductorsCharge Transfer At InterfacesCharge Transfer At Metal InterfacesElectron TransferEnergy Level SpacingsEnergy-level AlignmentInterfacial Reaction MechanismsMetal-semiconductor Interfaces
The energy-level alignment at interfaces between three electroactive conjugated organic materials and Au was systematically varied by adjusting the precoverage of the metal substrate with the electron acceptor tetrafluoro-tetracyanoquinodimethane (F4-TCNQ). Photoelectron spectroscopy revealed that electron transfer from Au to adsorbed F4-TCNQ was responsible for lowering the hole-injection barrier by as much as 1.2 eV. This novel interface modification scheme is independent of the charge transfer complex formation ability of the organic materials with the electron acceptor.
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