Ligand engineering of mid-infrared Ag2Se colloidal quantum dots

Shihab Bin Hafiz, Mohammad M. Al Mahfuz, Michael R. Scimeca, Sunghwan Lee, Soong Ju Oh, Ayaskanta Sahu, Dong Kyun Ko

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


Silver selenide colloidal quantum dots exhibit distinct optical absorption in the mid-wavelength infrared spectral region, which arises from the intraband transition between the first and the second quantum-confined energy levels. The optical absorption coefficient, carrier mobility, and carrier lifetime, which are the three primary parameters that determine the ultimate performance of a photodetector, are expected to be heavily dependent on the surface capping ligands. Herein, we characterize these parameters on silver selenide colloidal quantum dots films chemically treated with ligands selected from literatures that report high-performance quantum dot-based solar cells, photodetectors, transistors, and thermoelectrics. We correlate these results with the mid-infrared responsivities measured from photoconductive photodetectors fabricated from respective ligand-exchanged films. The insights gained from this study may serve as a foundation for enabling future intraband CQD-based MWIR sensing and imaging technologies.

Original languageEnglish
Article number114223
JournalPhysica E: Low-Dimensional Systems and Nanostructures
Publication statusPublished - 2020 Oct

Bibliographical note

Funding Information:
This work is/was supported by Global Research Outreach program of Samsung Advanced Institute of Technology as well as US National Science Foundation Grant No. ECCS-1809112 (DK) and ECCS-1809064 (AS) . We also gratefully acknowledge support for instrument use, scientific and technical assistance from the NYU Shared Instrumentation Facility through the Materials Research Science and Engineering Center (MRSEC) and MRI programs of the National Science Foundation under Award numbers DMR-1420073 and DMR-0923251 and the Imaging and Surface Science Facilities of Advanced Science Research Center at the Graduate Center of CUNY.

Publisher Copyright:
© 2020 Elsevier B.V.


  • Colloidal quantum dots
  • Mid-infrared
  • Photodetectors
  • Responsivity
  • Surface ligands

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics


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