1：Experimental Design and Method Selection:

The study involved the synthesis of PbS colloidal quantum dots (CQDs) in high-boiling-point organic solvents, followed by their deposition on substrates using the dip-coating method. The ligand exchange process was then performed to replace oleic acid molecules with S2? ions.

2：Sample Selection and Data Sources:

Hydrophobic PbS CQDs were synthesized and characterized for their spectral and luminescent properties. The samples were deposited on glass substrates and interdigitated gold electrodes for further analysis.

3：List of Experimental Equipment and Materials:

Chemicals used included lead(II) chloride, N,N'-diphenylthiourea, 1-octadecene, oleylamine, oleic acid, and others. Equipment included a Shimadzu UV-3101PC spectrophotometer, Ocean Optics USB-2000-FLG spectrofluorimeter, JEOL JEM-2100 transmission electron microscope, and a Solver PRO M atomic force microscope.

4：Experimental Procedures and Operational Workflow:

The synthesis of PbS CQDs was followed by their deposition on substrates using the dip-coating method. The ligand exchange process was then conducted, and the samples were characterized for their electrophysical properties under various light sources.

5：Data Analysis Methods:

The absorption and luminescence spectra of the CQDs were measured, and the current-voltage characteristics of the photodetector samples were analyzed to determine their photoconductivity and sensitivity to IR light.