Highly efficient and stable 2D-3D perovskite solar cells fabricated by interfacial modification

Area of Science:

• Materials Science
• Renewable Energy
• Solid-State Chemistry

Background:

• Two-dimensional (2D) perovskites offer enhanced stability over three-dimensional (3D) counterparts due to protective organic ligands.
• Despite advancements, 3D perovskites face challenges with stability and defects, limiting their practical application.

Purpose of the Study:

• To develop a stable 2D-3D hybrid perovskite structure for improved solar cell performance.
• To investigate the effect of n-butylammonium iodide (BAI) post-treatment on the stability and defect density of 3D perovskite films.

Main Methods:

• Fabrication of a 2D-3D hybrid perovskite by applying a BAI post-treatment to a 3D methylammonium lead iodide (CH3NH3PbI3) perovskite.
• Characterization of the 2D perovskite layer formation via chemical reaction between BAI and residual lead iodide (PbI2).
• Evaluation of the photovoltaic performance and long-term stability (light and air) of the fabricated solar cells.

Main Results:

• The BAI post-treatment successfully formed a protective 2D perovskite layer on the 3D perovskite surface.
• The 2D-3D hybrid perovskite exhibited significantly improved light and air stability compared to the pristine 3D perovskite.
• The resulting solar cells achieved a power conversion efficiency exceeding 18% and retained 80% of their initial efficiency after 2000 hours of storage without encapsulation.

Conclusions:

• The developed 2D-3D hybrid perovskite structure effectively passivates defects and enhances the intrinsic stability of 3D perovskite films.
• This post-treatment strategy offers a promising pathway for realizing highly stable and efficient perovskite solar cells.
• The optimized stoichiometry and defect passivation contribute to the superior performance and longevity of the hybrid perovskite solar cells.