Redox-Improved Self-Assembled Monolayers for Inverted Perovskite Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Nanotechnology

Background:

• Inverted perovskite solar cells (pero-SCs) show high power conversion efficiency (PCE) using nickel oxide (NiO_x)/self-assembled monolayer (SAM) hole transport layers (HTLs).
• Surface valence state variations in NiO_x complicate high-quality SAM HTL growth.

Purpose of the Study:

• To develop a new SAM molecule to address NiO_x surface complexities and improve HTL performance.
• To enhance the uniformity and coverage of SAM layers on NiO_x substrates.

Main Methods:

• Synthesis of a new SAM molecule, MeOF-4SHCz, targeting Ni³⁺-rich regions on NiO_x.
• Utilizing a redox reaction at the interface to form S-O-Ni bonds.
• Combining MeOF-4SHCz with MeOF-4PACz to create a mixed SAM HTL.

Main Results:

• The new SAM molecule facilitates the formation of a uniform and well-covered HTL on NiO_x.
• Optimized inverted pero-SCs with the redox-improved (ROI)-SAM HTL achieved a PCE of 26.5% (certified 26.28%).
• The optimized devices demonstrated enhanced stability, with T₉₀ exceeding 1000 hours.

Conclusions:

• The novel SAM molecule and its application in a mixed SAM HTL effectively overcome NiO_x surface challenges.
• This approach significantly boosts the PCE and operational stability of inverted pero-SCs.
• The findings offer a promising strategy for advancing perovskite solar cell technology.