Effect of preparation conditions for roughening gold substrate by oxidation-reduction cycle on the surface-enhanced Raman spectroscopy of polypyrrole

The surface-enhanced Raman spectroscopy (SERS) of polypyrrole (PPy) can be obtained by roughening the Au substrate with electrochemical oxidation-reduction cycle (ORC) before PPy deposition. The optimum condition for obtaining SERS effect is based on the strongest peak of C=C backbone stretching of PPy located at ca. 1600 cm^-1 shown in SERS. The optimum preparation conditions are as follows. Cathodic and anodic vertex potentials are -300 and 1200 mV vs. SCE, respectively. Delays at cathodic and anodic vertex potentials are 10 and 2 s, respectively. Cathodic and anodic scan rates are 500 and 1000 mVs^-1, respectively. The ORC cycle is 25 times. Also, the result indicates that the SERS effect decreases with increasing the charge passed for PPy deposition.