Steric-Hindrance-Engineered 1D/3D Heterojunction Unlocks Atomic-Level Matched Buried Interface for Efficient...

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Perovskite solar cells (PSCs) face challenges in long-term stability and commercial viability due to interfacial issues.
• Low-dimensional/three-dimensional (1D/3D or 2D/3D) perovskite heterojunctions offer a promising pathway for efficient PSCs.

Purpose of the Study:

• To address the interfacial stability of PSCs for improved long-term performance.
• To introduce a novel heterojunction interface using sulfonium-based molecules for atomic-scale lattice matching.

Main Methods:

• Symmetric sulfonium-based molecules with tunable alkyl spacers were synthesized and employed to create a buried heterojunction interface.
• The interface was characterized for its compatibility, steric hindrance, and templating effect on perovskite crystallization.
• Fabrication of 1D/3D PSCs utilizing the designed interface.

Main Results:

• The 1D interface facilitated uniform perovskite crystallization, alleviated stress, enhanced film quality, and prolonged carrier lifetime.
• The fabricated 1D/3D PSCs achieved a power conversion efficiency of 25.03% under AM 1.5 G illumination.
• The devices demonstrated excellent stability, retaining 94% of their initial efficiency after 1400 hours of aging in 55% relative humidity.

Conclusions:

• The developed sulfonium-based molecular interface effectively solves interfacial stability issues in PSCs.
• This interface design significantly boosts PSC efficiency, stability, and reproducibility.
• The findings pave the way for the commercial application of highly stable and efficient PSCs.