PbS Colloidal Quantum Dots Infrared Solar Cells: Defect Information and Passivation Strategies

Area of Science:

• Materials Science
• Nanotechnology
• Photovoltaics

Background:

• Large-sized lead sulfide quantum dots (PbS QDs) exhibit strong infrared absorption, suitable for bottom cells in tandem solar devices.
• Current quantum dot (QD)-based tandem solar cells exhibit underperformance compared to single-junction devices, necessitating further research.

Purpose of the Study:

• This review focuses on identifying and addressing defects in large-sized PbS QD solar cells.
• It examines defect origins during synthesis and fabrication, and summarizes passivation strategies to enhance device performance.

Main Methods:

• Analysis of defects arising from QD synthesis (oxidation, polydispersity, nonbonding sites).
• Investigation of ligand-exchange-related defects (tangled atoms, incomplete passivation, excess ligands).
• Examination of surface and interface defects during solar cell fabrication.

Main Results:

• Identified key defect sources in large-sized PbS QDs, including synthesis byproducts and ligand-exchange issues.
• Summarized effective passivation strategies such as cation exchange, controlled growth (thermodynamic and kinetic), mixed halide ligands, and post-treatments.
• Highlighted the potential of large-sized PbS QDs as efficient infrared absorbers.

Conclusions:

• Overcoming synthesis and fabrication defects is critical for realizing the full potential of large-sized PbS QDs.
• Effective passivation strategies are essential for improving the performance of both single-junction and tandem solar cells utilizing PbS QDs.