Afterglow Carbon Dots: From Fundamentals to Applications
(a) Phosphorescence of a CD-CA dispersion as a function of the concentration of Fe3+ in the mixture (0, 0.1, 0.2, 0.3, 0.4, 0.5, and 0.8 mM). (b) Linear response of to the concentration of Fe3+ ions. (c) The selectivity of the measurement of Fe3+ on the basis of the quenching of the phosphorescence of CD-CA (adapted and copyright permission  (a–c), Nature Publishing Group). (d) The dual response of the fluorescence and phosphorescence of CD powder to the change of temperature in the range of 30-90°C. (e) The fitted curves of the fluorescence and phosphorescence intensities as a function of temperature (adapted and copyright permission  (d, e), Royal Society of Chemistry). (f, g) Measured and fitted fluorescence intensity of P-CDs to pH in the region of 9.15 to 13.55. Inset showing the fluorescence images of an aqueous P-CD dispersion at different pH values. (h, i) Measured and fitted phosphorescence intensity of P-CDs as a function of pH in the region of 2.29 to 13.55. Inset showing the phosphorescence images of P-CD coated papers at different pH values (adapted and copyright permission  (f–i), Elsevier B.V.).