Tunable Tribovoltaic Effect via Metal-Insulator Transition

Area of Science:

• Materials Science
• Condensed Matter Physics
• Energy Harvesting

Background:

• Tribovoltaic nanogenerators are a promising technology for harvesting mechanical energy.
• Understanding mechano-electronic carrier dynamics at dynamic semiconductor interfaces is crucial for advancing this field.

Purpose of the Study:

• To investigate the tuning of the tribovoltaic direct-current (DC) effect using metal-insulator transition (MIT).
• To explore the impact of MIT on carrier excitation and transport in dynamic semiconductor heterojunctions.

Main Methods:

• Utilized vanadium dioxide (VO2), a representative MIT material.
• Investigated the tribovoltaic DC effect under static and dynamic heating conditions to induce MIT.
• Measured short-circuit current (ISC) and open-circuit voltage (VOC) changes.

Main Results:

• Demonstrated a >20-fold enhancement in short-circuit current (ISC) when VO2 transitioned from insulating to metallic state.
• Observed that the open-circuit voltage (VOC) remained largely unaffected by the MIT.
• Correlated the observed phenomena with the Hubbard model for Mott insulators.

Conclusions:

• The tribovoltaic DC effect can be effectively tuned by leveraging metal-insulator transitions.
• The significant increase in conductivity during MIT, rather than changes in excitation energy, drives the enhanced current output.
• This work provides fundamental insights into mechano-electronic properties of MIT materials for advanced energy harvesting applications.