Spectra-selective PbS quantum dot infrared photodetectors

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Traditional photoconductive photodetectors (PDs) exhibit broad spectral responses, often exceeding their material bandgaps.
• Detecting specific light spectra requires advanced photodetector designs beyond conventional approaches.

Purpose of the Study:

• To develop novel spectra-selective photodetectors (ss-PDs) using lead sulfide quantum dots (QDs).
• To demonstrate the ability to tailor the detection spectrum and range by tuning QD size.
• To showcase the application of these ss-PDs in identifying unknown light sources.

Main Methods:

• Fabrication of ss-PDs by integrating two functional layers: a perovskite/QD or QD/QD top layer for spectral filtering and a bottom detection layer.
• Tuning the spectral response and detection range by adjusting the size of the QDs.
• Characterization of selectivity factor and normalized detectivity under target and non-target illumination.

Main Results:

• Achieved spectra-selective detection with selectivity factors and normalized detectivity ratios of at least 10.
• Demonstrated a narrow detection range with a full width at half maximum (FWHM) of approximately 100 nm using QD/QD based ss-PDs.
• Successfully utilized prototype ss-PDs for identifying an unknown light source.

Conclusions:

• QD-based ss-PDs offer convenient spectral tuning and identification capabilities.
• These ss-PDs provide a versatile platform for creating highly spectrum-selective photodetectors for specialized applications.
• The developed technology addresses the demand for precise spectral detection in various fields.