Rational Design of Medium-Bandgap Perovskite Solar Cells for Triple-Junction Si Tandems

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Perovskite triple-junction tandem solar cells offer higher theoretical efficiency than double-junction cells.
• Current performance lags behind theoretical limits, often due to suboptimal middle cell bandgaps limiting current density.
• Existing designs do not adequately address the specific needs of triple-tandem architectures.

Purpose of the Study:

• To establish comprehensive design rules for the middle cell in perovskite triple-tandem solar cells.
• To optimize the middle cell for maximum photocurrent density and overall tandem current density.
• To enhance the performance of perovskite/perovskite/Si 3-junction (3J) tandem solar cells.

Main Methods:

• Investigated the impact of thickness variations in medium-bandgap perovskite and electron-transporting layers.
• Analyzed spectral responses to filtered incident light to maximize middle-cell photocurrent.
• Applied interfacial defect passivation using PDAI2.

Main Results:

• Developed specific design rules for the middle cell tailored for triple-tandem applications.
• Achieved a high current density of 11 mA/cm2 for the perovskite/perovskite/Si 3J tandem solar cell.
• Reached a conversion efficiency of 24.96% after interfacial defect passivation.

Conclusions:

• Optimized middle cell design is crucial for unlocking the potential of perovskite triple-tandem solar cells.
• The proposed design rules significantly improve current density and overall efficiency.
• Further efficiency gains are achievable through targeted interfacial engineering.