Facile Conversion of Toxic Cigarette Butts to N,S-Codoped CarbonDots and Their Application in Fluorescent Film, Security Ink,Bioimaging, Sensing and Logic Gate Operation

摘要

The present work is emphasized on converting toxiccigarette butts (CBs) into highly fluorescent N,S-codoped carbondots by a facile hydrothermal approach and exploring their multipleapplications. The as-produced carbon dots (CBCDs) exhibitedbright and stable fluorescence with a quantum yield of 26% andused as a label-free probe for “on?off?on” sequential detection ofFe3+ and ascorbic acid (AA). The fluorescence of CBCDs can besignificantly quenched by Fe3+ ions through static quenching andrestored upon the subsequent addition of AA due to the reductionof Fe3+ to Fe2+ by AA. This nanoprobe presented great selectivityand excellent sensitivity to Fe3+ and AA with a detection limit of0.13 and 0.2 μM, respectively. Furthermore, the nanoprobe wasextended to biosystem (intracellular detection) and successfullyapplied for the detection of Fe3+ in real water (tap, bore, and pond)and AA in biological samples (human urine and serum). In addition, we have constructed an IMPLICATION logic gate basedon these unique sensing characteristics. The “visible?invisible” and “UV?visible” property explored their use as invisible ink forsecurity applications. Furthermore, highly photostable fluorescent polymer films were prepared by incorporating CBCDs inpoly(vinyl alcohol). It is anticipated that the strong and stable fluorescence emission nature of these films might find direct orindirect applications in various optical/optoelectronic devices, ranging from fluorescent displays to light-emitting diodes.