CuI passivation layer for stabilizing BiI₃-sensitized QDSSCs: long-term performance stability assessment.

Area of Science:

• Materials Science
• Renewable Energy
• Nanotechnology

Background:

• Quantum dot-sensitized solar cells (QDSSCs) suffer from performance instability.
• Electrolyte-induced degradation at the electron transport material (ETM)/quantum dot (QD) interface is a primary cause.
• This degradation pathway remains underexplored.

Purpose of the Study:

• To investigate passivation strategies for BiI3-sensitized QDSSCs.
• To improve the performance stability of these solar cells.
• To mitigate electrolyte-induced degradation at the ETM/QD interface.

Main Methods:

• Utilized lead iodide (PbI2) and copper iodide (CuI) as passivation layers.
• Employed BiI3 as the sensitizer in QDSSCs with solid-state electrolytes.
• Characterized device performance and stability over 30 days.
• Analyzed photoanode surface morphology using field emission scanning electron microscopy (FESEM).

Main Results:

• CuI passivation improved performance stability over 30 days, maintaining 73.58% of initial efficiency (6.55% max to 4.82%).
• PbI2 passivation showed inferior stability compared to CuI.
• CuI created a less defective photoanode surface, minimizing ETM/electrolyte contact and electrolyte leakage.
• Reduced leakage current and prevented sensitizer degradation under prolonged illumination.

Conclusions:

• CuI passivation layers effectively enhance the performance stability of BiI3-sensitized QDSSCs.
• CuI is superior to PbI2 for passivating the ETM/QD interface in these devices.
• The passivation strategy successfully addresses electrolyte-induced degradation, paving the way for more robust QDSSCs.