Probing charge transfer between molecular semiconductors and graphene

Area of Science:

• Materials Science
• Condensed Matter Physics
• Surface Science

Background:

• Graphene's unique electronic properties make it suitable for sensitive potentiometers.
• Organic semiconductor device performance is influenced by molecular alignment at electrode interfaces.
• Interfacial band engineering is key for graphene/organic semiconductor heterostructures.

Purpose of the Study:

• To demonstrate and investigate charge transfer between graphene and molecular semiconductors.
• To probe charge transfer dynamics during interfacial dipole formation.
• To understand the mechanism governing level alignment at graphene-organic interfaces.

Main Methods:

• In-situ measurements to directly observe charge transfer.
• Utilizing graphene-based field effect devices.
• Fabrication of graphene/organic semiconductor heterostructures with parahexaphenyl and C60.

Main Results:

• Direct evidence of charge transfer between graphene and parahexaphenyl/C60.
• Adsorbed molecules do not significantly alter graphene's electron scattering rates.
• Charge transfer is identified as the primary mechanism for level alignment.

Conclusions:

• The study quantifies charge transfer per molecule, indicating weak interactions.
• Graphene's electronic properties are modulated by charge transfer from adsorbed organic molecules.
• This work provides insights into interfacial engineering for graphene-based electronic devices.