Narrowband Photodetectors Based on Graphene/Lead Sulfide Quantum Dots Heterojunction
The nanomaterial lead sulfide quantum dot(PbS QD)is an important candidate for short-wave infrared(SWIR)photodetectors due to its high optical absorbance and size-tunable bandgap.Graphene/lead sulfide quantum dot heterojunction photodetectors were prepared by combining films of halogen ligand-substituted PbS QDs with monolayer graphene.The liquid-phase ligand exchange technique combined with a single-step spin-coating process was used to achieve uniform deposition of the PbS QDs films.This technique reduces the generation of defective states and simplifies the device prepa-ration process to meet the requirements of industrial production by enabling rapid deposition of the desired film thickness through the single-step spin-coating process.The performance of the device in the SWIR band was tested,and the results show that the photodetector responsivity at 1 550 nm is 1.26×104 A/W,which is significantly higher than that of other bands.It is confirmed that the device has the ability of narrow-band detection near the 1 550 nm band.In addition,the specific detectivity at 1 550 nm is as high as 1.49×1012 Jones,which indicates that the device has high detection sensitivity and potential for practical applications in the SWIR band.
phase transfer ligand exchangelead sulfide quantum dotgraphenephotodetectorinfrared detection
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