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

Large-sized lead sulfide quantum dots (PbS QDs) offer strong absorption in the infrared, making them suitable for bottom cells in tandem devices. However, current QD-based tandem devices underperform compared to single junction devices. This review focuses on defect information and passivation strategies in large-sized QD solar cells. Defects from oxidation, polydispersity, and nonbonding sites on the (001) facet during QD synthesis are examined. Ligand-exchange-related defects such as tangled atoms, incomplete passivation, and excess ligands are analyzed. Surface and interface defects resulting from solar cell fabrication are also discussed. Strategies including cation exchange, thermodynamic growth, kinetic growth, and mixed halide ligands are summarized. Post-treatment approaches could also help to address surface and interface defects. Large-sized PbS-QDs show promise as infrared radiation absorbers. Overcoming defects and implementing effective passivation strategies are crucial for single junction and tandem solar cells.