External Field-Tunable Internal Orbit-Orbit Interaction in Flexible Perovskites.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Optoelectronics

Background:

• Hybrid metal halide perovskites exhibit electron orbital and spin momenta due to s-p wave function hybridization.
• Exciton orbit-orbit interactions can manifest as short-range magnetic dipoles or long-range orbital polarizations, influencing optoelectronic properties.

Purpose of the Study:

• To investigate the electrical switching of orbit-orbit interactions in hybrid perovskites.
• To explore the potential for external control of internal electronic interactions in perovskite solar cells.

Main Methods:

• Utilized a flexible perovskite (MAPbI₃-Clₓ) solar cell device.
• Applied external voltages between forward (0.2 V) and reverse (-0.2 V) biases.
• Investigated temperature dependence of the observed phenomenon from 300 K to 250 K.

Main Results:

• Demonstrated electrical switching of orbit-orbit interaction between orbital magnetic dipoles and orbital polarizations.
• Observed that the bias-switchable interaction is temperature-dependent, becoming negligible at lower temperatures (250 K).
• Identified mobile ions driven by electrical fields as the mechanism for switching interactions.

Conclusions:

• Established an external electrical mechanism for controlling internal orbit-orbit interactions in hybrid perovskites.
• Highlighted the role of mobile ions in bias- and temperature-dependent switching of these interactions.
• Provided insights for tuning orbit-orbit interactions in flexible perovskites for advanced orbitronic applications.