In Situ Click Chemistry for Energy-Level-Tunable Mixed Self-Assembled Monolayers in Perovskite Solar Cells

Area of Science:

• Materials Science
• Chemical Engineering
• Photovoltaics

Background:

• Interfacial energy alignment is crucial for inverted perovskite solar cell (PSC) performance.
• Precisely tuning the electronic structures of self-assembled monolayers (SAMs) for ideal alignment is challenging.

Purpose of the Study:

• To develop a novel strategy for constructing mixed SAMs with tunable energy levels.
• To achieve seamless energy alignment and improve interfacial properties in PSCs.

Main Methods:

• An *in-situ* click chemistry strategy under mild conditions was employed.
• Mixed SAMs were constructed by modulating precursor ratios, enabling simultaneous molecular coupling and energy-level modulation.
• Computational calculations and optoelectronic characterizations were used to analyze interfacial properties and charge transport.

Main Results:

• The strategy enabled seamless energy alignment (ΔE ≈ 0.01 eV) and improved interfacial properties.
• Reduced electron localization in SAMs facilitated enhanced charge transport.
• Mixed SAMs/perovskite interfaces demonstrated enhanced hole extraction and suppressed nonradiative recombination.

Conclusions:

• The developed click chemistry strategy offers a reliable method for precise energy-level tuning in mixed SAMs.
• This approach significantly enhances PSC performance, achieving a power conversion efficiency (PCE) of 26.83%.
• The strategy ensures excellent operational stability, maintaining 93% efficiency after 2,000 hours, and shows broad applicability across different perovskite compositions.