Unraveling the Emission Pathways in Copper Indium Sulfide Quantum Dots

Chenghui Xia, Philippe Tamarat, Lei Hou, Serena Busatto, Johannes D. Meeldijk, Celso De Mello Donega, Brahim Lounis*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


Semiconductor copper indium sulfide quantum dots are emerging as promising alternatives to cadmium-and lead-based chalcogenides in solar cells, luminescent solar concentrators, and deep-Tissue bioimaging due to their inherently lower toxicity and outstanding photoluminescence properties. However, the nature of their emission pathways remains a subject of debate. Using low-Temperature single quantum dot spectroscopy on core-shell copper indium sulfide nanocrystals, we observe two subpopulations of particles with distinct spectral features. The first class shows sharp resolution-limited emission lines that are attributed to zero-phonon recombination lines of a long-lived band-edge exciton. Such emission results from the perfect passivation of the copper indium sulfide core by the zinc sulfide shell and points to an inversion in the band-edge hole levels. The second class exhibits ultrabroad spectra regardless of the temperature, which is a signature of the extrinsic self-Trapping of the hole assisted by defects in imperfectly passivated quantum dots.
Original languageEnglish
Pages (from-to)17573-17581
Number of pages9
JournalACS Nano
Issue number11
Publication statusPublished - 23 Nov 2021


  • core-shell nanocrystals
  • exciton
  • exciton self-Trapping
  • exciton-phonon coupling
  • fine structure
  • single dot spectroscopy


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