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Investigating Process Factors on Red-shift of Photoluminescence of Carbon Dots

Feghhi, Fazeleh | 2019

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 53325 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Madah Hosseini, Hamid Reza
  7. Abstract:
  8. In recent years, studies in luminescent carbon dots are overgrowing, the prominent features of carbon quantum dots include cheap and straightforward synthesis, excellent biocompatibility, and adjustable optical properties. However, the widespread use of carbon dots in biomedical diagnostics, photoluminescence, and photocatalysis has been limited due to a lack of emission and excitation in the red or near-infrared region.. However, the widespread use of carbon dots in biomedical diagnostics, photoluminescence, and photocatalysis has been limited due to a lack of emission and excitation in the red or near-infrared region. This research tried to produce carbon dots with redshift in emission wavelength and good optical stability. Two methods synthesize these carbon dots, once by pyrolysis and surface modification, with cysteine; and by nitrogen and sulfur, using cysteine as a precursor in the solvothermal method. Some process parameters such as solvent, carbonizing acid, and nucleating agents during the solvothermal process are studied. Finally, the optical and structural properties of carbon points are investigated. According to PL results, carbon dots with a 110 nm redshift at 570 nm and efficiencies up to 2.4 times the original dots are obtained, and their energy gap is calculated by absorbing light in UV-Vis spectroscopy. EDS and FTIR identify nitrogen and sulfur doping in the structure of carbon dots and surface functional groups. DLS and HR-TEM and FESEM were used to determine the size and distribution of carbon dots
  9. Keywords:
  10. Carbon Dots ; Carbon Nanoparticles ; Graphene ; Luminescence ; Red Shift ; Quantum Dots

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