Selective Bidentate Coordination Reconstructs Residual PbI₂ to Homogenize Interfacial Energetics in Perovskite Solar...

Area of Science:

• Materials Science
• Chemical Engineering
• Renewable Energy

Background:

• Heterogeneous interfacial energetics from residual lead iodide (PbI2) limit perovskite solar cell performance and stability.
• Existing passivation methods using monodentate ligands or polar solvents show limited effectiveness or disrupt the perovskite structure.

Purpose of the Study:

• To develop a novel passivation strategy for residual PbI2 in perovskite photovoltaics.
• To improve the efficiency and operational stability of perovskite solar cells through selective PbI2 reconstruction.

Main Methods:

• A diammonium bidentate ligand (MeXT) was designed for dual-site coordination.
• Selective reconstruction of residual PbI2 into corner-sharing PbI6 octahedra was achieved.
• Passivation was performed while preserving the bulk perovskite structure.

Main Results:

• The MeXT ligand stabilized PbI6 units and created homogeneous interfacial energetics.
• Perovskite solar cells with MeXT achieved 26.19% power conversion efficiency.
• Devices maintained over 80% of initial efficiency after 1000 hours of 1-sun illumination at 75 °C.

Conclusions:

• The dual-anchor coordination passivation strategy offers a general design principle for treating residual PbI2.
• This method creates electronically coherent and operationally stable interfaces in perovskite photovoltaics.
• The findings pave the way for more stable and efficient perovskite solar cell technologies.