Effect of crystalline orientations of gold substrate on the surface-enhanced Raman scattering of electrochemically deposited polypyrrole

The polypyrrole (PPy) films were electrochemically deposited on gold substrates with dominant crystalline orientations of (1 1 1) and (2 2 0), respectively. The results indicated the redox behavior and the corresponding complex occurring and forming, respectively, on the gold substrate in 0.1 M KCl in oxidation–reduction cycles (ORC) were strongly sensitive to the crystalline orientation of substrates. Moreover, the surface-enhanced Raman scattering (SERS) intensity of PPy deposited on gold with a dominant (1 1 1) orientation is three fold higher than that of PPy deposited on gold with a dominant (2 2 0) orientation.