Photo-ferroelectric perovskite interfaces for boosting V_OC in efficient perovskite solar cells

Area of Science:

• Materials Science
• Renewable Energy
• Solid-State Physics

Background:

• Interface engineering is crucial for optimizing perovskite photovoltaic (PV) devices.
• Current PVs face limitations due to unavoidable open-circuit voltage (V_OC) losses, primarily from recombination.
• Existing strategies focus on interface chemistry to mitigate recombination.

Purpose of the Study:

• To introduce a novel photo-ferroelectric perovskite interface for enhanced PV performance.
• To leverage the electric field from a ferroelectric layer to improve charge separation and minimize recombination.
• To achieve higher open-circuit voltage (V_OC) and overall efficiency in perovskite solar cells.

Main Methods:

• Engineered an ultrathin ferroelectric two-dimensional (2D) perovskite layer sandwiching a perovskite bulk.
• Utilized the external polarization-induced electric field in the 2D layer.
• Performed device characterization and computational modeling of the interface.

Main Results:

• Achieved a record open-circuit voltage (V_OC) of 1.21 V.
• Attained a champion power conversion efficiency of 24%.
• Modeling confirmed coherent crystal and electronic structure matching, robust against defects.

Conclusions:

• The photo-ferroelectric interface effectively enhances charge separation and minimizes interfacial recombination.
• This approach provides a new strategy for reducing V_OC losses in perovskite PVs.
• The photoferroelectric field offers a tunable mechanism for advanced perovskite device design.