Preparation,Characterization And Properties Of Copper-based Gold/Silver Nanostructures

Metal nanostructures have become a hot topic in the current research field,owing to their excellent properties such as electronics,optics,magnetism,and physicochemical catalysis,and are widely applied in surface enhanced Raman scattering?SERS?.In this paper,centimeter level copper nanostructures with different morphology were prepared by a solid-state ionics method under different current electric field using the suitable fast ionic conductor films,the fractal dimension of dentritic nanostructures was calculated and its formation mechanism was also discussed.The new composite nanostructures?CuAu composite nanostructures and CuAg composite nanostructures?were prepared by vacuum thermal evaporation method on the basis of a solid-state ionics method.The surface morphology of the three groups nanostructures were characterized by scanning electron microscopy?SEM?and the chemical composition of the nanostructures were measured by energy dispersive spectrometer?EDS?.Raman enhancement performance of the nanostructures substrates was detected by Rhodamine 6G?R6G?aqueous solutions as probe molecules by confocal micro-Raman spectrometer.The main contents are as follows:The optimum parameters of fast ionic conductor films and metal electrodes were determined according to a large number of experiments.Copper nanostructures with different micromorphology were prepared by using fast ionic conductor Rb₄Cu₁₆Cl₁₃I₇ films with high ionic conductivity as transmission medium of copper ions,copper films as electrodes and controlling the applied current intensity.The influence of applied current intensity on the morphology of copper nanostructures was studied and it is found that the nanostructures arrangement can be controlled by adjusting current in the current range suitable for the growth of nanostructures.The growth mechanism of the copper nanostructures with macroscopic dentritic was associated with apical growth advantage.As the application of metal nanostructures in SERS,Raman enhancement performance of the copper nanostructures substrates was detected by R6G aqueous solutions.The results showed that the length of copper nanostructures with short-range orderly arrangement and high surface roughness was about 5centimeters under 3?A direct current electric field,the fractal dimension was 1.27 and the diameters of nanowires ranged from 50 to 130nm,the limiting concentrations of R6G for the prepared copper nanostructures SERS substrates is 10^-11 mol/L.The CuAu composite nanostructures and CuAg composite nanostructures were prepared by vacuum thermal evaporation method on the basis of a solid-state ionics method by depositing gold and silver particles on the surface of copper nanostructures.Raman enhancement performance of the two prepared composite nanostructures as SERS substrates was detected by R6G aqueous solutions.The results showed that the length of CuAu composite nanostructures with short-range orderly arrangement and high surface roughness was about 5centimeters under 7?A direct current electric field,the diameters of nanowires ranged from 30to 110nm and the limiting concentrations of R6G for the prepared the CuAu composite nanostructures SERS substrates is 10^-13 mol/L.The length of CuAg composite nanostructures with short-range orderly arrangement and high surface roughness was about 7 centimeters under 7?A direct current electric field,the diameters of nanowires ranged from 40 to 120nm and the nanostructures as SERS substrates can detect the complete set of Raman signals of10^-14mol/L R6G.The types of metal elements and surface roughness of SERS substrates are the two important factors for obtaining SERS with high enhancement performance.Under the visible light excitation condition,copper nanostructures had strong Raman enhancement performance,copper nanostructures can obtain higher surface roughness by depositing gold and silver particles,so the prepared metal composite nanostructures have higher SERS effect.