Science Advances

This PDF file includes:

• fig. S1. The AFM images of the as-exfoliated MoS₂ nanosheets with only sonication-assisted LPE and without cryo-pretreatment.
  
• fig. S2. XRD patterns of the as-obtained QDs and raw powder of layered materials.
  
• fig. S3. XPS spectra of the as-obtained QDs.
  
• fig. S4. XPS spectra of the corresponding raw bulk powders.
  
• fig. S5. UV-Vis absorbance spectra of MoS₂ samples with a series of cycles of cryo-pretreatment and liquid exfoliation treatment.
  
• fig. S6. Digital image of MoS₂ supernatants without vacuum filtration with series cycles of cryo-pretreatment and liquid exfoliation.
  
• fig. S7. AFM images of MoS₂ QDs produced in different solvents.
  
• fig. S8. The thickness statistics of the as-exfoliated GQDs with different cryp-pretreatment duration and solvents.
  
• fig. S9. Photoluminescence spectra excited at different wavelengths for MoS₂ QDs and WS₂ QDs.
  
• fig. S10. Tauc plots used to determine the optical bandgaps of various 2D QDs derived from UV-vis spectra.
  
• fig. S11. XRD pattern of the as-synthesized MoTe₂ powders.
  
• fig. S12. The AFM image of the MoS₂ sample obtained in a process with 1-hour gap between the cryo-pretreatment and the ultrasonication.
  
• fig. S13. ICP-MS results of the WS₂ QDs concentration with different sonication time at a fixed cryo-pretreatment duration of 1 hour.
  
• fig. S14. Thickness statistics of the as-exfoliated MoS₂ QDs and the background thickness signal of the new mica substrate.
  
• table S1. Surface tension and polar/dispersive ratio of the solvents adopted for the cryo-exfoliation of MoS₂.

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