Gate-controlled suppression of light-driven proton transport through graphene electrodes

Area of Science:

• Materials Science
• Physical Chemistry
• Nanotechnology

Background:

• Proton transport through graphene electrodes is crucial for energy applications.
• Low intensity illumination was previously shown to significantly accelerate this transport.
• Understanding the mechanisms controlling this photo-effect is essential for optimizing devices.

Purpose of the Study:

• To investigate the suppression of the light-induced acceleration of proton transport in graphene.
• To demonstrate the tunability of this photo-effect using voltage bias.
• To elucidate the underlying physical mechanisms, specifically the role of Fermi energy and Pauli blocking.

Main Methods:

• Utilizing photocurrent measurements to quantify proton transport rates.
• Employing Raman spectroscopy to probe electronic properties of graphene.
• Applying voltage bias to tune the Fermi energy of graphene electrodes.

Main Results:

• The photo-effect accelerating proton transport can be suppressed by applying a voltage bias.
• The suppression is selective for a tunable fraction of the infra-red spectrum.
• Tuning the Fermi energy of graphene via bias controls the suppression through Pauli blocking of photo-excited electrons.

Conclusions:

• Graphene's electronic and proton transport properties are interdependent.
• Voltage-controlled Pauli blocking offers a mechanism to modulate light-driven proton transport.
• These findings offer fundamental insights into electrode-electrolyte interfaces and light interactions at the nanoscale.