Fully textured monolithic perovskite/silicon tandem solar cells with 25.2% power conversion efficiency

Area of Science:

• Materials Science
• Renewable Energy Engineering
• Photovoltaics

Background:

• Perovskite/silicon tandem solar cells offer high efficiency potential (>30%) at competitive costs.
• Current methods require front-side polishing of silicon bottom cells, increasing costs and reducing light trapping.
• This polishing step is a barrier to cost-effective, high-performance tandem solar device manufacturing.

Purpose of the Study:

• To develop a perovskite top cell deposition process compatible with textured silicon.
• To enable conformal growth of perovskite materials on micro-pyramids of silicon.
• To achieve high-efficiency monolithic perovskite/silicon tandem solar cells without silicon front-side polishing.

Main Methods:

• Developed a novel top cell deposition technique for perovskite/silicon tandem devices.
• Utilized conformal growth of multiple compounds with controlled optoelectronic properties.
• Integrated a silicon heterojunction cell with a nanocrystalline silicon recombination junction.
• Employed textured monocrystalline silicon with micro-sized pyramids as the bottom cell.

Main Results:

• Achieved a certified steady-state power conversion efficiency of 25.2% for the tandem device.
• Demonstrated a current density of 19.5 mA cm⁻² due to optimized optical design and silicon pyramidal texture.
• Successfully deposited perovskite materials conformally on textured silicon surfaces.

Conclusions:

• The developed top cell deposition process eliminates the need for silicon front-side polishing.
• This approach overcomes limitations of current tandem solar cell fabrication, reducing costs and improving light management.
• Paves the way for cost-effective manufacturing of monolithic perovskite/silicon tandem solar cells exceeding 30% efficiency.