PTAA-Based Perovskite Photovoltaics Catching up: Ionic Liquid Engineering-Assisted Crystallization Through Sequential...

Area of Science:

• Materials Science
• Chemical Engineering
• Renewable Energy

Background:

• Poly(triarylamine) (PTAA) is a stable hole-transporting material, but PTAA-based devices show lower performance than those using oxides or self-assembled monolayers (SAMs).
• Improving perovskite film quality is crucial for efficient and stable solar cell devices.

Purpose of the Study:

• To enhance the performance and stability of perovskite solar cells by incorporating an ionic liquid into the precursor solution.
• To investigate the effect of EMIMCOOH on the morphology and properties of lead iodide (PbI2) films and subsequent perovskite conversion.

Main Methods:

• Introduction of 1-ethyl-3-methylimidazolium formate (EMIMCOOH) into the lead iodide (PbI2) precursor solution.
• Characterization of the resulting PbI2 films and perovskite layers using techniques like conducting atomic force microscopy (c-AFM).

Main Results:

• EMIMCOOH forms coordination bonds with Pb2+, creating a more mesoporous PbI2 film with improved pore structure.
• The ionic liquid addition slows perovskite conversion, leading to larger perovskite domains, reduced trap density, and enhanced charge transport.
• Achieved a power conversion efficiency (PCE) of 24.10% with a fill factor over 85%.

Conclusions:

• EMIMCOOH incorporation significantly improves perovskite film quality and device performance.
• The modified devices demonstrate enhanced stability, retaining 86% of their initial PCE after 1500 hours at 25°C in a nitrogen atmosphere.