Two-dimensional lead halide perovskite lateral homojunctions enabled by phase pinning

Area of Science:

• Materials Science
• Solid-State Physics
• Chemistry

Background:

• Two-dimensional (2D) organic-inorganic hybrid halide perovskites exhibit diverse structural polymorphs.
• These polymorphs offer tunable physical properties, crucial for semiconductor applications like homojunctions.
• Spacer cation order-disorder transitions influence perovskite properties.

Purpose of the Study:

• To demonstrate a space-cation-dopant-induced phase stabilization approach.
• To create a lateral homojunction within a 2D perovskite using ordered and disordered phases.
• To explore tunable optical properties and exciton diffusion in engineered perovskite homojunctions.

Main Methods:

• Doping 2D perovskites (e.g., (butylammonium)2PbI4) with small amounts of different spacer cations (e.g., pentylammonium).
• Inducing phase pinning of the disordered phase by suppressing cation ordering transitions.
• Utilizing temperature and pressure stimuli to control phase transitions and epitaxial growth.

Main Results:

• Successfully created a lateral homojunction composed of ordered and disordered phases in a 2D perovskite.
• Demonstrated phase pinning of the disordered phase via spacer cation doping.
• Achieved tunable optical properties and directional exciton diffusion across the homojunction interface.

Conclusions:

• Developed a novel strategy for constructing 2D perovskite homojunctions through thermodynamic tuning and spacer cation doping.
• Established a method for phase stabilization, enabling the creation of functional heterostructures.
• Highlighted the potential of engineered 2D perovskites for advanced semiconductor devices.