Stable PbS colloidal quantum dot inks enable blade-coating infrared solar cells.

Area of Science:

• Materials Science
• Photovoltaics
• Nanotechnology

Background:

• Infrared solar cells offer improved efficiency by reducing spectral loss in the near-infrared region.
• Lead sulfide (PbS) colloidal quantum dots (QDs) are promising for infrared photovoltaics due to their tunable bandgap.
• Current QD solar cell fabrication relies on small-area spin-coating and suffers from unstable QD inks.

Purpose of the Study:

• Investigate the mechanism of QD ink stability using Lewis acid-base and colloid stability theories.
• Develop a stable QD ink compatible with scalable manufacturing methods.
• Enable large-area fabrication of high-performance infrared PbS QD solar cells.

Main Methods:

• Utilized Lewis acid-base theory and colloid stability theory to understand QD ink stabilization.
• Developed a mixed solvent system (dimethylformamide and butylamine) suitable for blade coating.
• Fabricated large-area (100 cm²) uniform PbS QD films using blade coating.

Main Results:

• Achieved high power conversion efficiencies for PbS QD solar cells fabricated by blade coating (average 11.14% under AM1.5G, 4.28% filtered at 800 nm).
• Demonstrated excellent stability of the developed QD ink, with minimal performance degradation after 7 hours of storage.
• The fabricated films were uniform and dense, indicating successful large-area deposition.

Conclusions:

• A stable PbS QD ink and a compatible mixed solvent system were successfully developed.
• This advancement is crucial for the scalable manufacture of large-area blade-coated photoelectric devices.
• The findings pave the way for efficient and cost-effective infrared solar cell production.