Antisolvent-Free Dual-Anion Regulation for High-Efficient Sn-Pb and All-perovskite Tandem Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Mixed tin-lead (Sn-Pb) perovskites are key for all-perovskite tandem solar cells (TSCs) to exceed single-junction limits.
• Challenges include Sn-Pb perovskite film crystallization and Sn²⁺ oxidation, limiting device performance and stability.

Purpose of the Study:

• To develop a dual-anion synergistic regulation strategy for fabricating high-quality, MA-free Cs_0.1FA_0.9Pb_0.5Sn_0.5I₃ perovskite thin films.
• To improve morphology, crystallinity, and stability of Sn-Pb perovskite solar cells (PSCs) and TSCs using an antisolvent-free process.

Main Methods:

• Employed a multifunctional dual-anion synergistic regulation strategy using acetate (Ac^-) and thiocyanate (SCN^-) anions.
• Utilized a simplified antisolvent-free spin-coating process for perovskite thin film fabrication.
• Investigated anion exchange and coordination interactions to control crystallization and prevent Sn²⁺ oxidation.

Main Results:

• Achieved superior morphology and crystallinity in MA-free Cs_0.1FA_0.9Pb_0.5Sn_0.5I₃ perovskite films.
• The champion single-junction Sn-Pb PSC reached a power conversion efficiency (PCE) of 23.26%.
• All-perovskite TSCs achieved 28.07% efficiency with 81% performance retention after 600 hours.

Conclusions:

• The dual-anion strategy effectively regulates crystallization, mitigates Sn²⁺ oxidation, minimizes grain boundaries, and suppresses recombination.
• This approach sets a new benchmark for antisolvent-free Sn-Pb PSCs and enhances TSC performance and operational stability.