Hot Carrier Extraction with Plasmonic Broadband Absorbers.

Area of Science:

• Materials Science
• Nanotechnology
• Physical Chemistry

Background:

• Hot charge carrier extraction from metallic nanostructures is crucial for photocatalysis, photovoltaics, and photodetection.
• Current limitations include single plasmon resonance in nanostructures, restricting activity to a narrow spectral band.

Purpose of the Study:

• To achieve broadband light absorption in plasmonic nanostructures for enhanced light-to-charge-carrier activity.
• To investigate the impact of broadband absorption on photon-to-electron conversion efficiency.
• To develop a model for understanding hot electron generation and separation.

Main Methods:

• Assembling a monolayer of plasmonic nanoparticles on a multistack layered configuration.
• Utilizing broadband light absorption localized on the nanoparticle layer.
• Developing a physical model for plasmonic hot electron dynamics.

Main Results:

• Achieved broadband, near-unit light absorption across the nanoparticle layer.
• Demonstrated a ~40-fold increase in photon-to-electron conversion efficiency.
• Developed a model that accurately captures hot electron generation and separation physics.

Conclusions:

• Multistack layered configurations with plasmonic nanoparticles enable broadband light absorption.
• Enhanced light absorption significantly boosts photon-to-electron conversion efficiency.
• Efficient hot carrier extraction is contingent on photon energy exceeding Schottky barriers and localized light absorption.