Construction Of Fluorescent Thin Film Devices Based On Copper Nanoclusters For Mercury Ions Detection

Copper is one of the most widely used metals in the world.Copper-based nanomaterials have been widely used in different fields due to their environmentally friendly properties,economical cost of manufacturing,ease of obtainability and very high efficiency in sensing and electrocatalytic applications.Among the copper-based nanomaterials,the most well-known are Cu nanoparticles(Cu NPs).The Cu nanoclusters(Cu NCs)are formed when the size of these nano-materials were further reduced due to restrictions,and Cu NCs are one of the most important materials derived from copper.Cu NCs are clusters of copper atoms with a size of about 2 nm,which consist of a metallic core containing tens to hundreds of atoms protected by ligands.These Cu NCs have exceptional physicochemical properties such as excellent fluorescence characteristics,ultra-small size and good biocompatibility which have attracted wide attention because of its great potential in clinical diagnosis,nanotherapy,chemical catalysis,biosensing and bioimaging.In this paper,copper nanoclusters(Cu NCs@PATP)were synthesized in a volume ratio of 2:1 from 4-aminophenylthiophenol(PATP)solution with a concentration of 200 mM and CuCl2 2H2O solution with a concentration of 5mM.,and the fluorescence and Raman spectroscopy,TEM,MALDI-TOF,TGA,and XPS were used to analyze the physical and chemical properties of Cu NCs@PATP.The results showed that the excitation wavelength of Cu NCs@PATP was 365nm and the emission wavelength was 602nm,the average particle size was 2.16±0.36 nm and its structure is Cu2(SR)4(SR=C6H6NS).In addition,we found that it can be used for the analysis and detection of Hg(Ⅱ),the fluorescence spectrum can be used to determine that when Cu NCs@PATP is dispersed in deionized water,it has a good response to Hg(Ⅱ)in the concentration range of 25ppt-25ppb,and the detection limit is 10ppt(S/N is 3).In the experiment,it was found that the material was unstable,so the dialdehyde cellulose(DAC)was introduced to combine with the material,and the fluorescence life of the material was extended to 14 days significantly without affecting its fluorescence performance,and a fluorescent colorimetric card was developed by virtue of the characteristic of DAC that is easy to form film.Taking the lake water of Shangde Lake in TEDA campus of Tianjin University of Science and Technology as an actual sample,quantitative Hg(Ⅱ)was added to it and determined by ICP-MS,and then the application ability of the prepared fluorescence colorimetric card was analyzed.It was found that the colorimetric card could detect the lowest concentration of Hg(Ⅱ)at 10 ppb.The fluorescence specific colorimetric card prepared in this experiment has the characteristics of result visualization,short time and low cost,which provides a new method for the detection of Hg(Ⅱ)in water.At the same time,the use of DAC in this experiment also provides a new idea for extending Cu NCs@PATP to improve its stability.