Monolithic Perovskite/Silicon Tandem Solar Cells Enabled by Multifunctional TiO_x Interconnects

Area of Science:

• Materials Science
• Renewable Energy
• Nanotechnology

Background:

• Perovskite-silicon tandem solar cells offer high power conversion efficiencies (PCE) exceeding 30%.
• Complex multilayer designs hinder mass production scalability.
• Multifunctional nanolayers are needed to simplify fabrication.

Purpose of the Study:

• To develop a simplified interconnection method for perovskite-silicon tandem solar cells.
• To investigate the potential of a multifunctional TiOₓ nanolayer for large-scale manufacturing.
• To improve the efficiency and reduce the cost of tandem solar cell production.

Main Methods:

• Atomic layer deposition (ALD) of a TiOₓ nanolayer (∼3-5 nm) for direct interconnection.
• Utilizing TiOₓ for silicon surface passivation, hole extraction, and recombination junction.
• Employing ALD-TiN<0xE1><0xB5><0xA7> capping for performance enhancement.

Main Results:

• A proof-of-concept tandem solar cell achieved 22.4% PCE.
• An improved PCE of 26.5% was obtained with a TiOₓ/TiN<0xE1><0xB5><0xA7> nanolayer.
• The performance matched reference devices using complex interlayers.

Conclusions:

• A multifunctional TiOₓ nanolayer simplifies perovskite-silicon tandem solar cell fabrication.
• This approach reduces manufacturing complexity and eliminates the need for indium-based interlayers.
• The developed nanolayer offers a pathway for low-cost, scalable, and sustainable tandem solar cell manufacturing.