Highly mobile hot holes in Cs₂AgBiBr₆ double perovskite

Area of Science:

• Materials Science
• Solid-State Physics
• Optoelectronics

Background:

• Efficient hot carrier optoelectronics depend on highly mobile hot charge carriers for long-range transport.
• Carrier-phonon scattering typically hinders hot carrier mobility, making them less mobile than cold carriers.

Purpose of the Study:

• To report and investigate enhanced hot carrier mobility in Cs2AgBiBr6 double perovskite.
• To explore the fundamental mechanisms behind hot carrier transport in this material.

Main Methods:

• Optical pump–infrared push-terahertz probe spectroscopy.
• Frequency-resolved photoconductivity measurements.

Main Results:

• Achieved up to a fourfold enhancement in hot carrier mobility compared to cold carriers.
• Demonstrated long-range hot carrier transport exceeding 200 nm.
• Identified hot holes with reduced momentum scattering as the primary source of conductivity enhancement.

Conclusions:

• Cs2AgBiBr6 exhibits boosted hot carrier mobility due to reduced momentum scattering, enabling (quasi-)ballistic transport.
• This material serves as a promising platform for fundamental studies and applications in hot carrier optoelectronics.