Thermal Spin Coated PbS QD SWIR Imager for Non-Invasive Glucose Monitoring

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Colloidal lead sulfide quantum dots offer tunable bandgaps for short-wave infrared photodetectors.
• Current limitations include high dark current, poor carrier extraction, and instability.

Purpose of the Study:

• To improve quantum dot film quality and photodetector performance using a novel deposition strategy.
• To enhance device stability and explore new applications.

Main Methods:

• Combined thermal spin-coating and annealing to control solvent evaporation and quantum dot stacking.
• Optimized substrate temperature during spin-coating for dense film formation.
• Fabricated and characterized photodetectors at an optimized temperature (65°C).

Main Results:

• Achieved enhanced photodetector performance: 0.765 A/W responsivity, 3.57 × 10¹¹ Jones detectivity, 108 kHz bandwidth.
• Reduced dark current density by over 50%.
• Demonstrated improved long-term stability and higher external quantum efficiency without encapsulation.

Conclusions:

• Thermal spin-coating is a scalable method for high-performance, stable quantum dot infrared photodetectors.
• Optimized photodetectors were integrated into an imaging array for non-invasive glucose monitoring.
• This approach enables advanced imaging and biomedical sensing applications.