Highly Stable Sn─Pb Perovskite Solar Cells Enabled by Phenol-Functionalized Hole Transporting Material

Area of Science:

• Materials Science
• Photovoltaics
• Organic Chemistry

Background:

• Tin-lead (Sn─Pb) perovskites are promising low bandgap semiconductors for multi-junction solar cells.
• Device instability, primarily due to Sn²⁺ oxidation, limits their practical application.

Purpose of the Study:

• To enhance the stability and performance of Sn─Pb perovskite solar cells.
• To introduce a multi-functional polymer (PF─OH) with antioxidative properties.

Main Methods:

• Designed and synthesized a polymer (PF─OH) incorporating fluorine and phenol units.
• Incorporated PF─OH into Sn─Pb perovskite devices to improve Sn²⁺ oxidation energy barrier.
• Investigated the effects of PF─OH on perovskite crystallization, film morphology, and carrier lifetime.

Main Results:

• PF─OH significantly enhanced Sn─Pb perovskite device stability from 200 to 8000 hours (100-fold improvement).
• Improved perovskite film quality with fewer pinholes and extended carrier lifetimes.
• Achieved a power conversion efficiency (PCE) of 23.61% with enhanced operational stability.

Conclusions:

• The developed polymer (PF─OH) effectively suppresses Sn²⁺ oxidation, dramatically improving perovskite device stability.
• The strategy of incorporating phenol units offers a universal approach for stabilizing Sn─Pb perovskites.
• This work represents a significant advancement in developing durable and efficient Sn─Pb perovskite solar cells.