The aim of this study
was to investigate how the oxidation state
of copper (Cu(I) vs Cu(II)), the nature of the interface (solid/aqueous
vs solid/air), positional isomerism, and incubation time affect the
functionalization of the surface of copper oxide nanostructures by
[(butylamino)(pyridine)methyl]phenylphosphinic acid (PyPA). For this
purpose, 2-, 3-, and 4-isomers of PyPA and the nanostructures were
synthesized. The nanostructure were characterized by UV-visible spectroscopy
(UV–vis), scanning electron microscopy (SEM), Raman spectroscopy
(RS), and X-ray diffraction (XRD) analysis, which proved the formation
of spherical Cu
2
O nanoparticles (Cu
2
ONPs; 1500–600
nm) and leaf-like CuO nanostructures (CuONSs; 80–180/400–700
nm, width/length). PyPA isomers were deposited on the surface of NSs,
and adsorption was investigated by surface-enhanced Raman scattering
(SERS) and tip-enhanced Raman scattering (TERS). The changes of adsorption
on the surface of copper oxide NSs caused by the above-mentioned factors
were described and the enhancement factor on this substrate was calculated.