Electric field-induced assembly of Au-Ag alloy nanoparticles into nano-reticulation for ultrasensitive SERS

This paper discusses a method for assembling Au-Ag alloy nanoparticles (NPs) using direct current (DC) electric field to fabricate highly active SERS substrates. Different nanostructures could be obtained by regulating the intensity and action time of DC electric field. Under the condition of 5mA*10 min, we obtained Au-Ag alloy nano-reticulation (ANR) substrate with excellent SERS activity (Enhancement factor on order of magnitude of 106). ANR substrate has excellent SERS performance due to the resonance matching between its LSPR mode and excitation wavelength. The uniformity of the Raman signal on ANR is greatly improved than bare ITO glass. ANR substrate also has the ability to detect multiple molecules: ANR substrate can respectively detect Rh6G and CV molecules with a concentration as low as 10-10 M and 10-9 M and the Raman spectral intensity of the probe molecules on the surface of the ANR substrate has good linear correlation with the molecular concentration (R2 > 0.95). In addition, ANR substrate can detect both thiram and aspartame (APM) molecules far below (thiram for 0.0024 ppm and APM for 0.0625 g/L) the safety standard, which demonstrate its practical application potential.

Automated summary

This paper discusses a method for fabricating highly active SERS substrates by assembling Au-Ag alloy nanoparticles (NPs) using a direct current (DC) electric field. Different nanostructures can be obtained by adjusting the intensity and action time of the DC electric field. The Au-Ag alloy nano-reticulation (ANR) substrate obtained under the condition of 5mA*10 min shows excellent SERS activity with an enhancement factor of the order of magnitude of 106. The ANR substrate has good uniformity of Raman signal and can detect multiple molecules with low concentrations. It also has potential for practical applications as it can detect molecules far below the safety standard.