Edge/Corner-Sharing 2D Perovskite Functional Layer for Efficient and Stable Inverted Perovskite Solar Cells

Area of Science:

• Materials Science
• Photovoltaics
• Solid-State Chemistry

Background:

• Tuning surface structure in 2D perovskites is crucial for efficient perovskite solar cells (PSCs).
• Narrow octahedral interlayer spacing is key to mitigating confinement effects and improving carrier transport.
• Achieving optimal interfacial energy-level matching and carrier kinetics remains a challenge.

Purpose of the Study:

• To engineer an n-type 2D perovskite functional layer with controlled octahedral connectivity.
• To reduce quantum and dielectric confinement effects in inverted PSCs.
• To enhance carrier mobility and interfacial energy-level alignment for improved solar cell performance.

Main Methods:

• Constructed an n-type 2D perovskite (2D-MEDAPb2I6) layer on a 3D perovskite film surface.
• Utilized N-methylethylenediamine cations (MEDA2+) to regulate [PbI6]4- octahedral connection modes.
• Achieved edge/corner-sharing (E/C-sharing) octahedral framework, resulting in a narrow interlayer spacing of 8.39 Å.

Main Results:

• The 2D-MEDAPb2I6 layer exhibited the narrowest interlayer spacing among 2D perovskites, enhancing interlayer coupling.
• Quantum and dielectric confinement effects were significantly weakened, boosting carrier mobility.
• A type-II 3D/2D heterojunction was formed, lowering interfacial energy barriers and reducing carrier recombination.
• Achieved a certified power conversion efficiency of 26.10% (optimal 26.43%) and maintained >94% efficiency after 1200 hours.

Conclusions:

• The novel E/C-sharing 2D perovskite strategy effectively tunes surface structure and enhances PSC performance.
• This approach provides a new pathway for developing advanced 2D perovskites for photovoltaics.
• The developed 2D capping layer improves lattice stability and carrier dynamics, leading to highly efficient and stable inverted PSCs.