Highly efficient and stable perovskite photovoltaics enabled by multifunctional crosslinked n⁺-type interlayer.

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Tin dioxide (SnO2) is a key electron transport layer in perovskite solar cells (PSCs).
• Interfacial defects and energy-level misalignment at the SnO2/perovskite interface limit PSC performance and commercialization.
• Existing strategies struggle to effectively mitigate these interfacial issues.

Purpose of the Study:

• To engineer a multifunctional polymeric interlayer for the SnO2/perovskite interface.
• To enhance interfacial adhesion, dissipate stress, and passivate defects.
• To improve energy-level alignment for efficient charge extraction in PSCs.

Main Methods:

• Introduction of polymerizable dimethyldiallylammonium chloride (DADMAC) to form a P-DADMAC interlayer.
• Cross-linking of P-DADMAC to create a robust network.
• Passivation of defects using chloride ions and engineering of band bending.

Main Results:

• Achieved a power conversion efficiency (PCE) of 26.34% for n-i-p devices, with a certified PCE of 26.27%.
• Demonstrated a fill factor (FF) of 85.84% for individual devices and >80% for a 25 cm² module.
• Reduced heterojunction energy-level offset by 0.24 eV, facilitating charge extraction and minimizing non-radiative losses.

Conclusions:

• The P-DADMAC interlayer effectively passivates interfacial defects and optimizes energy levels in PSCs.
• This multifunctional interfacial engineering approach enables high-performance and scalable perovskite solar cells.
• The strategy provides a new paradigm for advancing photovoltaic device technology.