A Multidentate Coordination Complex-Based Self-Assembled Monolayer Stabilizes Perovskite Interface

Area of Science:

• Materials Science
• Photovoltaics
• Surface Chemistry

Background:

• Self-assembled monolayers (SAMs) are vital for hole-selective contacts in perovskite solar cells.
• Existing SAMs with single phosphonic acid groups suffer from desorption and poor perovskite precursor interaction.
• This limits interfacial film quality and device performance.

Purpose of the Study:

• To develop a robust co-SAM component for stabilizing buried interfaces in perovskite photovoltaics.
• To enhance substrate anchoring and interfacial coupling with perovskite precursors.
• To improve perovskite crystallization and overall device stability and efficiency.

Main Methods:

• Synthesized and employed a multidentate Fe(III) porphyrin complex as a co-SAM.
• Utilized four phosphonic acid groups for tetradentate chelation with oxide substrates.
• Investigated the effect of the Fe center and axial chloride ligand on perovskite precursor interaction and surface properties.

Main Results:

• The Fe(III) porphyrin complex increased substrate adsorption energy by over threefold.
• Apparent surface energy increased by ~30%, and contact angle decreased by ~40%, enhancing wettability.
• Achieved 27.06% power conversion efficiency in small-area devices and 24.1% in modules (21.54 cm²).

Conclusions:

• Coordination-complex-based SAMs offer a promising strategy for stabilizing buried interfaces in perovskite solar cells.
• The multidentate porphyrin complex significantly improves device efficiency and operational stability.
• This approach paves the way for more durable and efficient perovskite photovoltaic technologies.