Efficient and Stable Tin-Lead Mixed Perovskite Solar Cells Using Post-Treatment Additive with Synergistic Effects.

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Oxidation of Sn²⁺ during Sn-Pb mixed perovskite film crystallization is a critical challenge for high efficiency.
• Existing methods focus on precursor solution stability, but in-situ oxidation during crystallization is less explored.

Purpose of the Study:

• To investigate the role of antioxidants during Sn-Pb mixed perovskite film crystallization.
• To develop a novel additive that prevents Sn²⁺ oxidation and enhances perovskite solar cell performance and stability.

Main Methods:

• Introduction of 2,5-di-tert-butylhydroquinone (DBHQ), a functional alterable additive, into Sn-Pb mixed perovskite films via an anti-solvent approach.
• Characterization of perovskite film quality, photovoltaic performance, and long-term/thermal stability of the fabricated solar cells.

Main Results:

• DBHQ effectively inhibits Sn²⁺ oxidation during crystallization, leading to higher quality perovskite films.
• The oxidation product of DBHQ, 2,5-di-tert-butyl-1,4-benzoquinone (DBBQ), acts as a defect passivator, reducing charge recombination.
• DBHQ-modified Sn-Pb mixed perovskite solar cells (PSCs) achieved a power conversion efficiency (PCE) of 23.0%, compared to 19.6% for the reference.
• Unencapsulated devices showed excellent stability, retaining 84.2% and 78.9% of initial PCE after 800h at 25°C and 120h at 60°C, respectively.

Conclusions:

• The functional alterable strategy using DBHQ offers a novel approach for high-performance Sn-Pb mixed PSCs.
• DBHQ simultaneously addresses oxidation during crystallization and defect passivation, leading to enhanced efficiency and stability.