Efficient tandem solar cells with solution-processed perovskite on textured crystalline silicon

Area of Science:

• Photovoltaics
• Materials Science
• Renewable Energy

Background:

• Single-junction solar cells face theoretical efficiency limits (Shockley-Queisser limit).
• Perovskite solar cells offer high single-junction efficiencies (>20%) but face challenges in monolithic integration with silicon.
• Tandem solar cells, stacking cells with different band gaps, promise higher efficiencies.

Purpose of the Study:

• To develop efficient monolithic perovskite-silicon tandem solar cells.
• To overcome charge-collection limitations in thick perovskite layers.
• To improve the stability and performance of perovskite-silicon tandem devices.

Main Methods:

• Fabrication of monolithic tandems combining solution-processed perovskite top cells with textured silicon heterojunction bottom cells.
• Enhancement of depletion width at silicon pyramid bases to improve charge collection.
• Surface passivation of perovskites using 1-butanethiol to improve diffusion length and suppress phase segregation.

Main Results:

• Achieved a certified power conversion efficiency of 25.7% for perovskite-silicon tandem solar cells.
• Demonstrated negligible performance loss after 400 hours of thermal stability testing at 85°C.
• Showed negligible performance loss after 400 hours under maximum power point tracking at 40°C.

Conclusions:

• Successful monolithic integration of solution-processed perovskites with textured silicon heterojunctions is demonstrated.
• Enhanced charge collection and material stability lead to high-efficiency, durable perovskite-silicon tandem solar cells.
• These findings pave the way for overcoming the Shockley-Queisser limit in photovoltaics using tandem architectures.