Robust Imidazole-Linked Covalent Organic Framework Enabling Crystallization Regulation and Bulk Defect Passivation...

Area of Science:

• Materials Science
• Renewable Energy
• Nanotechnology

Background:

• Low crystallinity and defects in perovskite layers hinder perovskite solar cell (PSC) performance and stability.
• Grain boundaries and interfaces are critical sites for performance degradation in PSCs.

Purpose of the Study:

• To introduce a photoelectric imidazole-linked porphyrin-based covalent organic framework (PyPor-COF) for improved PSCs.
• To utilize PyPor-COF for precise control over perovskite crystallization and defect passivation.

Main Methods:

• Sequential deposition method incorporating PyPor-COF.
• Utilizing the porous channels and active sites of PyPor-COF to regulate PbI2 crystallization and eliminate defects.
• Leveraging the electronic properties of PyPor-COF for enhanced energy level alignment and charge transport.

Main Results:

• PyPor-COF facilitated controlled perovskite crystallization and defect passivation.
• Achieved champion PSCs with power conversion efficiencies of 24.10% (0.09 cm²) and 20.81% (1.0 cm²).
• Optimized devices retained 80.39% of initial efficiency after 2000 hours of air exposure, demonstrating excellent thermal and light stability.

Conclusions:

• PyPor-COF effectively addresses key challenges in PSC development.
• This approach offers a new strategy for creating highly efficient and stable perovskite solar cells.
• The study highlights the potential of covalent organic frameworks in advancing photovoltaic technologies.