Study On Preparation And Properties Of Ginger Carbon Dots

As a new type of fluorescent carbon nanomaterial,carbon dot（CDs）has been developed rapidly due to its excellent fluorescence performance,simple synthesis method,good biocompatibility and wide range of detection applications.Compared with traditional semiconductor quantum dots and organic dyes,luminous CDs not only has advantages in water solubility,photobleaching resistance,toxicity,photostability,biocompatibility and other aspects,but also has excellent photoluminescence properties,which makes it has a wide range of applications in light-emitting devices,biological imaging,biological sensing and other aspects.In recent years,more and more attention has been paid to the synthesis of CDs using green carbon source as precursor.However,green CDs is limited due to low emission intensity and single emission wavelength.Therefore,the research on improving the effectiveness and repeatability of CDs luminescence intensity,polychromatic emission will promote its applications in sensing,imaging,heavy metal detection and other aspects.In addition,the fluorescence intensity of CDs is affected by the surface states and the structure and size of the material.So far,scientists have done systematic research on enhancing fluorescence intensity and multi-color tunable spectroscopy.Using small molecules and renewable resources as precursors and using heating,microwave radiation and ultrasound as synthesis methods,the research mainly focuses on the preparation and application of CDs from natural sources.In particular,cheap,easily available and environmentally friendly biomass raw material resources have great potential as precursors of CDs preparation.A simple and green synthesis method was established.Fluorescent CDs was prepared from fresh ginger juice under the condition of hydrothermal or microwave radiation.Main research contents of this paper are as follows:（1）Using freshly squeezed ginger juice as raw material,CDs was synthesized by hydrothermal or microwave radiation method.The results showed that the CDs was small in size,evenly distributed and contained three elements C,O and N.Fluorescence properties research shows that ginger CDs with fluorescence properties,fluorescent stability,salt stability is good,in different p H in the solution,the fluorescence intensity change,in neutral and weak alkali conditions fluorescence intensity change is small,under acid condition and the strong alkaline condition change of fluorescence intensity is bigger,therefore,ginger CDs has good anti-interference ability.Comparing the two methods,it can be found that the former can quickly synthesize fluorescent CDs at low temperature,while the latter can significantly shorten the synthesis time.（2）The application of ginger CDs as a fluorescent probe in metal ions was systematically studied.These results showed that ginger CDs could recognize Fe³⁺quickly and specifically.CDs solution prepared by hydrothermal method showed a good linear relationship,and the detection limit was 0.18μm.The CDs solution prepared by microwave method also showed good linearity,and the detection limit was 0.89μm.Further study and analysis showed that Fe³⁺and energy coordinated with groups on the surface of CDs to generate non-luminous complexes,which resulted in fluorescence quenching of CDs,namely static quenching of the two.This method was applied to real samples,and the recoveries were 96%～102.18%,with RSD of 1.52%～2.69%（n=3）.In order to further study ginger CDs,silver/copper composite ginger CDs was prepared.The morphology and optical properties were measured by scanning electron microscope,fluorescence spectrum and absorption spectrum.It was found that CDs of silver composite prepared by in-situ composite method had better fluorescence properties.Nano materials have antibacterial effect,so their antibacterial effect was tested.The results showed that the antibacterial activity of ginger CDs compound of silver/copper was higher than that of pure CDs solution.An antimicrobial nanocomposite film has excellent antimicrobial properties,light transmittance and flexibility,which provides a theoretical basis for the application of novel antimicrobial nanomaterials in agricultural antimicrobial film.