Two-dimensional perovskite templates for durable, efficient formamidinium perovskite solar cells

Area of Science:

• Materials Science
• Solid-State Chemistry
• Photovoltaics

Background:

• Formamidinium lead iodide (FAPbI3) is a promising material for perovskite solar cells.
• Achieving stable, phase-pure FAPbI3 films remains a significant challenge.
• Current fabrication methods often require high annealing temperatures, impacting stability.

Purpose of the Study:

• To develop a novel strategy for fabricating ultrastable, phase-pure FAPbI3 films.
• To utilize lattice templating with 2D perovskites for improved FAPbI3 film formation.
• To enhance the efficiency and durability of FAPbI3-based solar cells.

Main Methods:

• Fabrication of FAPbI3 films via lattice templating using specific 2D perovskites.
• Annealing the FAPbI3 precursor solution at a reduced temperature (100°C).
• Characterization using X-ray diffraction and optical spectroscopy.

Main Results:

• Formation of phase-pure, black FAPbI3 at 100°C, significantly lower than the standard 150°C.
• Observed slight compression of FAPbI3 films to match the (011) interplanar distances of the 2D perovskite template.
• Achieved 24.1% power conversion efficiency in p-i-n solar cells with 0.5 cm² active area.
• Demonstrated exceptional durability, retaining 97% efficiency after 1000 hours at 85°C under maximum power point tracking.

Conclusions:

• Lattice templating with 2D perovskites is an effective strategy for fabricating ultrastable FAPbI3 films.
• The method enables lower processing temperatures and improves the intrinsic stability of FAPbI3.
• This approach holds significant potential for advancing the commercial viability of perovskite solar cells.