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Red/orange dual-emissive carbon dots for pH sensing and cell imaging


The dual-emissive N, S co-doped carbon dots (N, S-CDs) with a long emission wavelength were synthesized via solvothermal method. The N, S-CDs possess relatively high photoluminescence (PL) quantum yield (QY) (35.7%) towards near-infrared fluorescent peak up to 648 nm. With the advanced characterization techniques including X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), etc. It is found that the doped N, S elements play an important role in the formation of high QY CDs. The N, S-CDs exist distinct pH-sensitive feature with reversible fluorescence in a good linear relationship with pH values in the range of 1.0–13.0. What is more, N, S-CDs can be used as an ultrasensitive Ag+ probe sensor with the resolution up to 0.4 μM. This finding will expand the application of as prepared N, S-CDs in sensing and environmental fields.


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We thank Beijing Nova Program Interdisciplinary Studies Cooperative Project (No. Z181100006218138), Science Foundation of China University of Petroleum-Beijing (No. 2462018BJC004), National Key Specialty Construction Project of Clinical Pharmacy (No. 30305030698) and Research Funding of Sichuan Provincial People’s Hospital (No. 2017LY08) for the support.

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Correspondence to Lulu Cai or Quan Xu.

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Zhang, M., Su, R., Zhong, J. et al. Red/orange dual-emissive carbon dots for pH sensing and cell imaging. Nano Res. 12, 815–821 (2019).

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  • carbon cell imaging
  • dual-emissive
  • photoluminescence
  • pH-sensitive
  • Ag+ probe