Synthesis of partially embedded bimetallic gold-silver nanostructures for sucrose sensing applications

30 keV Ag⁻ ion implantation on Au thin film, 5 nm, deposited on glass substrates produces partially embedded bimetallic AuAg alloy nanostructures. Low energy Ag⁻ ion implantation is utilized to simultaneously achieve two objectives: first, it irradiates the Au thin layer, and second, it incorporates Ag atoms into the glass substrates. The investigations using Atomic Force Microscopy (AFM) reveal that the Ag^- ion implantation caused nanostructuring of the partially embedded irregularly shaped and spherical shaped nanostructures on glass substrates. The particle mean size is (37.5 ± 6.8) nm and the height profiles vary from 0 to 12 nm. The average separation distance between the particles is 131 nm, which indicates good separation. Measurements with Rutherford Backscattering Spectrometry (RBS) show mixing of Au atoms with Ag atoms in the host substrate, indicating alloy formation. Further, the results of UV–Vis (Surface Plasmon Resonance) absorption studies show only one SPR absorbance peak in the absorption spectra, that also support the synthesis of bimetallic AuAg alloy nanoparticles (NPs) in glass substrates. The mechanisms of production of partially embedded alloy nanostructure on the glass surface are explained by crater formation, sputtering; inter particle diffusion and mixing due to thermal spike caused by low energy Ag⁻ ion implantation. Sucrose sensing has been explored on these glass thin films comprising partially embedded bimetallic AuAg alloy nanostructures. Without the need for a probe, the SPRs of bimetallic AuAg alloy nanostructures are effective in detecting sucrose solutions, showing a noticeable blue shift (~ 11 nm) to 1 nM sucrose solution. However, there is no change in SPR position with further increase in concentration of sucrose solution. The result indicates complete coverage of NPs with 1 nM sucrose solution and detection limit is significantly lower than that of a 1 nM sucrose solution. The findings show that the sensing responses have potential applications in sensing of biomolecules.