Preparation And Properties Study Of Red-emitting Fluorescent Copper Nanoclusters

Traditional fluorescent materials include semiconductor quantum dots,organic dyes,polymer microspheres,inorganic complexes and others.However,the traditional fluorescent material cannot meet the various needs of new development attributed to their intrinsic characteristics,such as light bleaching effect,fluorescence tunability,biological toxicity and so on.Researchers have focused their attention on novel fluorescent metal nanomaterials,and the ultra-small fluorescent copper nanoclusters?Cu NCs?,due to their low cost,unique optical and electronic properties,have a wide range of application prospects in sensing,catalysis,fluorescence imaging,optoelectronic devices,drug delivery and other fields.The contents were as follows:1.In this work,we report a novel strategy for fabricating luminescent 2D nanocomposite at room temperature by in situ generating luminescent copper nanoclusters?Cu NCs?embedded in natural monolithic eggshell membrane?ESM?using dithiothreitol as reducing and capping agent.The established fabrication is facile,cost-effective and viable.The as-prepared Cu NCs/ESM nanocomposite exhibited excellent photoluminescence performance,improved chemical,thermal and photo stability,convenient tailoring and flexibility.Significantly,the nanocomposites could be employed as test strips for the visual detection of Ag⁺ions based on luminescence quenching phenomenon and as color conversion layers in the light-emitting diodes?LEDs?.Furthermore,application of the proposed strategy for surface luminescent patterning was well demonstrated,indicating bright potential in biomass based anti-counterfeiting,information encryption and security paper or sheet.2.In this work,we report a novel chemical approach for the synthesis of orange-red emitting copper nanoclusters?Cu NCs?using L-methionine as the stabilizing agent at room temperature for the first time.The synthetic route is facile,economical and viable.The resultant methionine stabilized copper nanoclusters?Cu NCs/Met?were thoroughly characterized by varieties of analysis methods.The results showed that the synthesized Cu NCs/Met possessed ultrasmall size?².7 nm?,high stability and excellent optical features such as large Stokes shift and long fluorescence lifetime.Significantly,the fluorescence intensity of Cu NCs/Met can be efficiently quenched by norfloxacin?NOR?pharmaceutical.A novel,fast and cost-effective NOR sensor was proposed employing Cu NCs/Met as the fluorescent nanoprobe conveniently,and the quenching mechanisms were attributed to the agglomeration-induced quenching and the primary inner filter effect?IFE?between Cu NCs/Met and NOR.The developed sensor exhibited a high sensitivity and selectivity towards NOR in a wide linear concentration range from 0.05 to 250?M with a detection limit as low as 17 nM?S/N=3?.Moreover,the practicability of the developed NOR sensor for real sample assay was validated with satisfactory recoveries,thus enabling this sensing platform promising for label-free detection of pharmaceutical molecules in complex systems.3.At present,the majority of reported fluorescent copper nanoclusters were synthesized using wet chemistry methods with complicated operations,and the as-prepared products dispersed in liquid phase have limited the applications of solid-state fluorescent copper nanoclusters greatly.In this paper,the solid-phase synthesis method at room temperature for luminescent copper nanoclusters was adopted.The powders of DTT and anhydrous copper sulfate were placed in an agate mortar and red fluorescent copper nanoclusters were prepared by uniform grinding and cryopreservation.The strategy is simple,rapid,and especially suitable for large-scale synthesis.Notably,based on the phenomenon of fluorescence enhancement,the“turn-on”Cd²⁺ions sensor was successfully developed employing the copper nanoclusters as fluorescent probes.The prepared fluorescent copper nanoclusters have a broad application prospect in the construction of LED devices as the light conversion materials.