Modulating phase composition and crystallization of 2D Ruddlesden-Popper perovskite films via a polyvinylidene...

Area of Science:

• Materials Science
• Renewable Energy
• Nanotechnology

Background:

• Two-dimensional (2D) Ruddlesden-Popper (RP) perovskite films face challenges with uncontrolled crystallization and phase distribution.
• Undesirable small-n phases, poor out-of-plane orientation, and high defect density hinder performance.
• Existing polymer interlayers offer limited clarification on mechanisms in quasi-2D systems.

Purpose of the Study:

• To develop an effective interfacial engineering strategy for controlling phase distribution in 2D RP perovskite films.
• To investigate the role of polyvinylidene fluoride (PVDF) as an ultra-thin interlayer.
• To enhance the morphology, crystallinity, and photovoltaic performance of perovskite solar cells.

Main Methods:

• Incorporation of an ultra-thin polyvinylidene fluoride (PVDF) interlayer at the buried interface of BA₂MA₃Pb₄I₁₃ perovskite films.
• Comprehensive characterization techniques to analyze film morphology, phase distribution, and crystallinity.
• Fabrication and performance testing of optimized 2D RP perovskite solar cells.

Main Results:

• The PVDF interlayer significantly suppressed the formation of low-n (n < 4) phases.
• Preferential out-of-plane orientation and enhanced crystallinity were observed in PVDF-modified films.
• Optimized devices exhibited improved charge transport properties.

Conclusions:

• Interfacial engineering with a PVDF interlayer is a viable strategy to control phase distribution in 2D RP perovskites.
• PVDF modification leads to enhanced film quality and improved solar cell performance.
• PVDF-modified 2D RP perovskite solar cells achieved a champion power conversion efficiency of 11.03%.