Highly Efficient Monolithic Perovskite/TOPCon Silicon Tandem Solar Cells Enabled by "Halide Locking".

Area of Science:

• Materials Science
• Renewable Energy
• Solid-State Physics

Background:

• Perovskite/silicon tandem solar cells (TSCs) show high power conversion efficiencies (PCEs).
• Controlling perovskite crystallization and composition on silicon is challenging, limiting TSC efficiency and stability.

Purpose of the Study:

• To address challenges in perovskite layer formation for TSCs.
• To enhance the uniformity and stability of perovskite films in TSCs.

Main Methods:

• Introduced a "halide locking" strategy using thioacetylacetamide hydrochloride (TAACl).
• TAACl modulates nucleation and crystal growth, ensuring compositional uniformity and preferred (001) orientation.
• Applied the method to wide-bandgap perovskite layers on silicon subcells.

Main Results:

• Achieved excellent compositional uniformity in perovskite films.
• Demonstrated enhanced film homogeneity over long length scales.
• Obtained high open-circuit voltage-fill factor (V_OC × FF) products in small and large-area devices.
• Record PCE of 31.32% for large-area TSCs using TOPCon silicon subcells, with V_OC of 1.931 V and FF of 81.54%.

Conclusions:

• The halide locking strategy effectively improves perovskite film quality for TSCs.
• This approach enables high-performance and stable large-area perovskite/silicon tandem solar cells.
• Achieved a record PCE, highlighting the potential for commercialization.