Long-Range Exciton Transport in Perovskite-Metal Organic Framework Solid Composites

Area of Science:

• Materials Science
• Nanotechnology
• Solid-State Physics

Background:

• Perovskite quantum dots (PQDs) encapsulated in metal-organic frameworks (MOFs) create PQDs@MOF composites with potential in optoelectronics, catalysis, and luminescence.
• The exciton diffusion distance is a critical factor for PQDs@MOF performance, but it remains largely unknown.

Purpose of the Study:

• To investigate and quantify the exciton diffusion distance and coefficient in MAPbBr3 PQDs@MOF microcrystals.
• To understand the factors contributing to exciton transport in these composite materials.

Main Methods:

• Utilized time-resolved and photoluminescence-scanned imaging microscopy.
• Fabricated MAPbBr3 PQDs@MOF microcrystals for analysis.

Main Results:

• Observed long-distance exciton transport of 278 ± 12.6 nm in MAPbBr3 PQDs@MOF.
• Measured a high exciton diffusion coefficient of 0.0428 ± 0.0039 cm²/s.
• Exciton diffusion length was found to be seven times longer than in colloidal PQD solid films.

Conclusions:

• Long exciton diffusion in PQDs@MOF is attributed to strong dipole-dipole coupling between PQDs and extended carrier lifetimes within the MOF matrix.
• PQDs@MOF crystals exhibit significant potential for advanced optoelectronic applications due to enhanced exciton transport.