Bifunctional Interface Passivation via Copper Acetylacetonate for Efficient and Stable Perovskite Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Interface defects in perovskite solar cells (PSCs) cause nonradiative recombination, hindering performance and stability.
• Effective passivation strategies are crucial for advancing PSC technology.

Purpose of the Study:

• To investigate copper acetylacetonate [Cu(acac)2] as an interface passivator for PSCs.
• To enhance the stability and power conversion efficiency of PSCs by minimizing interfacial defects.

Main Methods:

• Treated the interface between Spiro-OMeTAD and perovskite with Cu(acac)2.
• Analyzed the chelation reactions, defect suppression, and formation of protective layers.
• Evaluated the performance and long-term stability of the modified PSCs.

Main Results:

• Cu(acac)2 anchored at the interface and grain boundaries, forming multiple ligand bridges and p-type copper iodide.
• Suppressed deep-level defects (Pb0 and I0) near the perovskite interface, facilitating hole transfer.
• Hydrophobic Schiff base complexes formed, leading to tightly packed surfaces, sealed grain boundaries, and inhibited moisture diffusion.
• Achieved a champion efficiency exceeding 24% and retained approximately 92% of initial efficiency after 1680 hours.

Conclusions:

• Cu(acac)2 effectively passivates interface defects in PSCs.
• The passivation strategy significantly enhances both performance and long-term operational stability.
• This approach offers a promising route for developing highly efficient and durable perovskite solar cells.