Pure-Phase, Large-Grained Wide-Band-Gap Perovskite Films for High-Efficiency, Four-Terminal Perovskite/Silicon Tandem...

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Silicon-based tandem solar cells require high-quality, wide band gap perovskite films for efficiency and cost-competitiveness.
• Achieving stable perovskite films with desired optoelectronic properties remains a key challenge.

Purpose of the Study:

• To develop stable, wide band gap perovskite films using specific additive and annealing strategies.
• To enhance the efficiency of semitransparent perovskite solar cells (PSCs).
• To assemble and evaluate a four-terminal perovskite/TOPCon tandem solar cell.

Main Methods:

• Utilized Pb(SCN)2 additive and air annealing for Cs0.22FA0.78Pb(I0.85Br0.15)3 film fabrication.
• Characterized film properties including band gap, composition, crystallinity, grain size, and defect density.
• Fabricated semitransparent PSCs and a perovskite/TOPCon tandem solar cell.

Main Results:

• Achieved perovskite films with a wide band gap of 1.65 eV, pure composition, high crystallinity, micro-sized grains, and reduced defects.
• Increased average PSC efficiency from 18.13% to 20.35%.
• Demonstrated a perovskite/TOPCon tandem solar cell with a milestone efficiency of 30.32%.

Conclusions:

• Combined Pb(SCN)2 additive and air annealing strategies effectively produce high-quality, stable wide band gap perovskite films.
• The developed perovskite films significantly improve PSC performance and enable highly efficient tandem solar cells.
• The achieved 30.32% efficiency in a perovskite/TOPCon tandem solar cell represents a significant advancement in photovoltaic technology.