Ionic Liquid Gating Enhanced Photothermoelectric Conversion in Three-Dimensional Microporous Graphene

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• The photothermoelectric (PTE) effect converts light to electricity via photothermal and thermoelectric processes.
• Efficient PTE materials are crucial for light energy harvesting and photodetection, especially in the terahertz (THz) range.
• Three-dimensional microporous graphene (3DMG) foam shows promise due to high THz absorptivity and photothermal conversion.

Purpose of the Study:

• To enhance the THz PTE response of 3DMG foam.
• To investigate the use of ionic liquid electric double layer (EDL) gating for tuning thermoelectric properties.
• To improve light energy harvesting and THz radiation detection.

Main Methods:

• Utilized the ionic liquid electric double layer (EDL) technique to tune the thermoelectric properties of 3DMG foam.
• Employed continuous and reversible EDL gating to manipulate the electronic structure of the 3DMG.
• Fabricated a double-cell 3DMG EDL device with a p-n junction-like channel configuration.

Main Results:

• Demonstrated significant enhancement of the THz PTE response in 3DMG foam.
• Achieved approximately a 1-order of magnitude increase in the Seebeck coefficient and PTE responsivity.
• Observed further improvement in photoresponse with the double-cell device configuration.

Conclusions:

• The EDL gating technique effectively enhances the PTE performance of 3DMG foam.
• This method offers a new pathway for optimizing 2D nanosheet-assembled 3D porous materials for THz applications.
• The study paves the way for highly efficient THz energy harvesting and detection systems.