Conjugated Amine Ligand-Induced Robust-Conductive Interlayer Enables Efficient and Durable n-i-p Perovskite Solar...

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Low-dimensional/three-dimensional (LD/3D) perovskite heterojunctions show great potential in photovoltaics.
• Performance is limited by the trade-off between defect passivation and charge extraction.
• Cation migration and interfacial defects hinder operational stability.

Purpose of the Study:

• To reconcile high efficiency with operational stability in perovskite solar cells.
• To explore ammonium ligands for improved interfacial charge transport and suppressed cation migration.
• To design a surface modifier for 3D perovskite films to create a stable 1D protecting layer.

Main Methods:

• Designed a π-conjugated quaternary ammonium ligand, PCOZI (4-phenyl-1,3-oxazol-2-yl-heptyl-dimethylammonium iodide), as a surface modifier.
• Formed a stable 1D (PCOZ)PbI3 protecting layer on 3D perovskite films.
• Fabricated and characterized 1D/3D perovskite solar cells (PSCs) with the PCOZI interlayer.

Main Results:

• The PCOZI interlayer created a near-conformal and structurally ordered interface, balancing defect passivation and charge transfer.
• Optimized devices achieved a record power conversion efficiency (PCE) of 26.33% (certified 26.29%) for 1D/3D n-i-p PSCs.
• Devices retained 94.2% of initial PCE after 1000 hours of operation under ISOS-L-3 conditions.
• A minimodule achieved a PCE of 23.15% over a 10.24 cm² area, demonstrating scalability.

Conclusions:

• The PCOZI surface modifier effectively passivates defects and enhances charge transport in 3D perovskite films.
• This interfacial engineering approach reconciles high PCE with outstanding operational stability in PSCs.
• The developed strategy offers a scalable and practical solution for advancing perovskite solar cell technology.