Interface passivation for 31.25%-efficient perovskite/silicon tandem solar cells

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Silicon solar cells face theoretical efficiency limits around 29%.
• Tandem device architectures, stacking multiple solar cells, offer a path to exceed these limits by improving solar energy harvesting.
• Advanced device designs are crucial for next-generation solar energy technologies.

Purpose of the Study:

• To develop a tandem solar cell device combining perovskite and silicon to surpass the efficiency limitations of traditional silicon cells.
• To enhance photocurrent generation in the silicon bottom cell through conformal perovskite coating on micrometric pyramids.
• To mitigate recombination losses at the perovskite/electron-selective contact interface.

Main Methods:

• Fabrication of a tandem solar cell with a perovskite top layer conformally coated on a silicon bottom cell with industry-standard micrometric pyramids.
• Utilizing an additive during processing to control perovskite crystallization.
• Employing buckminsterfullerene (C60) as an electron-selective contact.

Main Results:

• Demonstration of a tandem solar cell with a 1.17 cm² active area.
• Achieved a certified power conversion efficiency of 31.25%, exceeding the theoretical limit of silicon-only cells.
• Successful regulation of perovskite crystallization and reduction of recombination losses.

Conclusions:

• The developed perovskite-silicon tandem solar cell architecture effectively overcomes the efficiency limitations of single-junction silicon cells.
• Controlling perovskite crystallization and minimizing interface recombination are key to achieving high power conversion efficiencies in tandem devices.
• This work demonstrates a viable pathway towards highly efficient solar energy conversion using advanced tandem photovoltaic technologies.