Synergistic Bulk and Interfacial Defect Control Boosts Voltage and Efficiency in Perovskite/Silicon Tandem Solar...

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Wide-bandgap perovskites in perovskite/silicon tandem solar cells (PSTSCs) suffer from open-circuit voltage (VOC) losses due to defect recombination and interfacial energy misalignment.
• These losses are critical obstacles to achieving higher power conversion efficiencies in PSTSCs.

Purpose of the Study:

• To introduce a synergistic bulk-to-surface defect passivation strategy for wide-bandgap perovskites.
• To simultaneously suppress defect formation during crystallization and optimize the perovskite/C60 interface in PSTSCs.

Main Methods:

• Incorporation of Dicyandiamide into the perovskite precursor to enhance vacancy formation energies and crystallinity.
• Surface treatment with ethane-1,2-diamine diacetate for concurrent passivation of cationic and anionic defects and energy-level alignment.
• Fabrication of monolithic PSTSCs utilizing the developed passivation strategy.

Main Results:

• Achieved a champion power conversion efficiency of 32.03% in monolithic PSTSCs.
• Obtained a high open-circuit voltage (VOC) of 1.95 V, indicating reduced nonradiative recombination losses.
• Demonstrated exceptional storage stability under ambient conditions.

Conclusions:

• Integrated bulk and interfacial defect control is crucial for overcoming voltage and efficiency limitations in wide-bandgap perovskite top cells for tandem photovoltaics.
• The synergistic passivation strategy effectively reduces defect-assisted recombination and improves energy-level alignment.
• The developed method offers a promising pathway towards highly efficient and stable PSTSCs.