Stable Sn/Pb-Based Perovskite Solar Cells with a Coherent 2D/3D Interface.

Area of Science:

• Materials Science
• Renewable Energy
• Solid-State Chemistry

Background:

• Low-band-gap mixed tin/lead perovskites are crucial for high-efficiency tandem solar cells.
• Instability in air, due to Sn²⁺ oxidation, hinders the practical application of these perovskites.

Purpose of the Study:

• To enhance the stability and performance of low-band-gap tin-based perovskite solar cells.
• To investigate the effect of N-(3-aminopropyl)-2-pyrrolidinone on perovskite film structure and stability.

Main Methods:

• Incorporation of N-(3-aminopropyl)-2-pyrrolidinone into CH₃NH₃Sn_0.5Pb_0.5I_xCl_3-x thin films.
• Formation of a 2D layered perovskite structure via Lewis acid coordination with Sn²⁺/Pb²⁺.
• Fabrication and characterization of 2D/3D hybrid perovskite solar cells.

Main Results:

• A vertically oriented 2D layered perovskite structure was formed, seamlessly integrated with the 3D bulk crystal.
• The resulting Sn-based perovskite solar cells achieved a power conversion efficiency exceeding 12%.
• The devices demonstrated remarkable stability, retaining 90% performance in ambient conditions and over 70% under continuous illumination for a month.

Conclusions:

• The 2D/3D hybrid structure effectively mitigates Sn²⁺ oxidation, significantly improving perovskite solar cell stability.
• N-(3-aminopropyl)-2-pyrrolidinone is a promising additive for developing stable and efficient tin-based perovskite solar cells.
• This approach offers a pathway towards robust and high-performance perovskite photovoltaic technologies.