Enhanced Raman scattering from copper phthalocyanine on Pt by use of a Weierstrass prism

It was demonstrated by theoretical calculation that the surface-plasmon-polariton-assisted Raman spectroscopy is quite useful to improve the sensitivity level of the Raman signal from adsorbates even on transition metals with higher intrinsic damping than silver (ɛ = −10.6 +i0.342). In fact, a remarkably large enhancement factor of ca. 300 was observed for Raman band intensity from copper phthalocyanine (CuPc) on platinum (ɛ = −8.34 +i14.2) using both in- and out-coupling of the SPP. Moreover, the preferred orientation of the CuPc molecules parallel to the platinum surface becomes evident by a decreased depolarization ratio of 1530 cm−1 (A1g) band for thinner CuPc adlayers, and an extremely dense aggregation of atomically flat Pt terraces of ca.10 × 10 × 10nm extension observed by STM.