Triple-junction solar cells with improved carrier and photon management

Area of Science:

• Materials Science
• Renewable Energy
• Semiconductor Physics

Background:

• Perovskite-silicon triple-junction solar cells promise higher efficiencies than dual-junction devices but face challenges.
• Key bottlenecks include low open-circuit voltage in the top cell and limited photocurrent in the middle cell.

Purpose of the Study:

• To address and overcome the primary limitations in perovskite-silicon triple-junction solar cells.
• To enhance open-circuit voltage and photocurrent generation for improved overall efficiency and stability.

Main Methods:

• Utilized 4-hydroxybenzylamine as a non-volatile additive to control perovskite crystallization and passivate defects in the wide-bandgap top cell.
• Implemented a three-step deposition strategy for thick, low-bandgap perovskite absorbers in the middle cell, improving electron extraction.
• Incorporated silicon oxide (SiO_x) nanoparticles as an optical middle-reflector in the silicon bottom cell to enhance light absorption.

Main Results:

• Achieved open-circuit voltages up to 1.405 V with enhanced stability in the top cell.
• Demonstrated improved microstructural integrity and electron extraction in the middle cell.
• Successfully fabricated 1 cm² perovskite-perovskite-silicon devices.

Conclusions:

• The developed strategies effectively mitigate bottlenecks in perovskite-silicon triple-junction solar cells.
• The optimized device architecture led to a certified power conversion efficiency of 30.02%.
• This work represents a significant advancement in high-efficiency photovoltaic technology.