Synthesis,Optical Properties And Applications Of Fluorinated Carbon Dots

Carbon dots(CDs)is a novel type of zero-dimension carbon nanomaterials with good physical,chemical,and biomedical properties,such as wide absorption spectrum,tunable fluorescence,excellent water solubility,outstanding photostability,and biocompatibility,which lead to a wide range of applications in the fields of fluorescence sensing,biological imaging,drug delivery and so on.In recent years,CDs have shown many novel optical phenomena due to their unique composition and structure,including phosphorescence,thermally activated delayed fluorescence,chemiluminescence,electrochemical luminescence,upconversion,near-infrared luminescence,mechanoluminescence.Among those,afterglow emission performance of CDs is one of the most attractive properties,which has been successfully applied in advanced fields such as anti-counterfeiting,information encryption,and sensing.This study primarily focused on the synthesis of fluorinated CDs(FCDs).FCDs and fluorine-nitrogen co-doped CDs(F,NCDs)with different properties were synthesized via high-temperature pyrolysis.The morphology,structure and properties of the as-prepared materials were characterized,and their optical properties and optical applications were further studied.The main contents and results of this study were as following:FCDs with high quantum yields were synthesized via high-temperature pyrolysis.Fluorocarbon-containing sodium carboxymethyl cellulose(FCDs-CMCNa)compounds with temperature-sensitive fluorescence/phosphorescence and good thermal stability were prepared through mixture of FCDs and sodium carboxymethyl cellulose(CMCNa).The method employed in this study for the preparation of FCDs-CMCNa was simple,rapid and industrially applicable.Based on the unique optical properties of FCDs-CMCNa,new optical materials with unique properties were expected to be developed under low-temperature conditions.The prepared FCDs-CMCNa had good photostability and room temperature phosphorescence(RTP)performance,which proved that FCDs-CMCNa had the potential to become a new type of RTP application material.Using soluble starch as the carbon source and levofloxacin as the dopant,F,NCDs were synthesized via high-temperature pyrolysis.MTT and LDH assays were performed to test the cytotoxicity of F,NCDs.Results showed that F,NCDs were safe bio-nanomaterials with low toxicity and capable for biological application.MTT and DCFH-DA assays were performed for qualitative analysis of the anti-tumor effects of F,NCDs under lighting conditions.Results proved that F,NCDs had the potential to become a new photodynamic therapy(PDT)photosensitizer.