Flexible perovskite/silicon tandem solar cell with a dual-buffer layer

Area of Science:

• Materials Science
• Renewable Energy
• Nanotechnology

Background:

• Perovskite/silicon tandem solar cells offer high power conversion efficiency (PCE) for next-generation photovoltaics.
• Mechanical stress and interfacial delamination are critical challenges for flexible tandem solar cells, hindering their long-term stability.

Purpose of the Study:

• To develop a dual-buffer-layer strategy with a stress-release mechanism to improve the mechanical stability and performance of flexible perovskite/silicon tandem solar cells.
• To mitigate ion bombardment during sputtering deposition and enhance interfacial adhesion without compromising charge extraction.

Main Methods:

• Engineered a dual-buffer layer using tin oxide (SnO_x) with varying atomic layer deposition (ALD) purging times.
• A loose SnO_x layer dissipates strain energy, while a compact SnO_x layer ensures electrical contact.
• Constructed flexible tandem solar cells on 60-micron-thick ultrathin silicon bottom cells.

Main Results:

• Achieved a certified PCE of 33.4% on a 1-cm² area and 29.8% on a 260-cm² wafer-sized area.
• Demonstrated excellent durability, retaining over 97% of initial PCE after 43,000 bending cycles and 250 thermal cycles (-40°C to 85°C).
• Achieved a high power-per-weight of up to 1.77 W/g.

Conclusions:

• The dual-buffer-layer strategy effectively enhances interfacial adhesion and mitigates mechanical stress in flexible perovskite/silicon tandem solar cells.
• This approach significantly improves device durability and maintains high power conversion efficiency, paving the way for robust, high-performance flexible solar technologies.