Acid-Base Complexation Induced Dipole Engineering for Durable Inverted Perovskite Photovoltaics

Area of Science:

• Materials Science
• Renewable Energy
• Physical Chemistry

Background:

• Buried interfaces in inverted perovskite solar cells (PSCs) are thermally unstable, limiting commercialization.
• Self-assembled monolayers (SAMs) used as hole-selective contacts suffer from poor coverage and weak thermal anchoring, causing energy losses and degradation.

Purpose of the Study:

• To address the limitations of SAMs in PSCs by developing a robust interfacial layer.
• To enhance hole extraction, power conversion efficiency (PCE), and thermal stability in inverted PSCs.

Main Methods:

• Incorporation of 4-aminopyridine (4-AP) into a Me-4PACz matrix to create an electrostatic complex via acid-base complexation.
• Dipole-engineering strategy to enhance interfacial dipole moment and molecular orientation.
• Fabrication and characterization of small-area and large-area inverted PSCs and modules.

Main Results:

• Achieved a PCE of 27.06% for small-area (0.09 cm²) inverted PSCs with a V_OC of 1.194 V.
• Demonstrated large-area (655.2 cm²) modules with 20.3% efficiency and a fill factor of 79.9%.
• Devices retained over 90% of initial PCE after 1000 h at 85°C and 200 thermal cycles, showing exceptional thermal stability.

Conclusions:

• The dipole-engineering strategy using electrostatic complexation significantly improves interfacial properties and device performance.
• This approach offers a generalizable pathway for creating durable and high-performance perovskite photovoltaics.
• Supramolecular interactions are key to achieving enhanced interfacial dipole engineering for advanced solar cell technologies.