A study of thin solid organic films by Fourier transform surface-enhanced Raman scattering and atomic force microscopy

Fourier transform surface-enhanced Raman scattering (FT-SERS) in the near-infrared and atomic force microscopy (AFM) have been used to characterize thin solid organic films. The pigments studied were phthalocyanines and perylenes which have applications as charge generation materials in organic photoreceptors. Techniques for film preparation such as Langmuir-Blodgett (LB) deposition and vacuum evaporation are discussed. The literature was reviewed for FT-Raman spectroscopy, surface-enhanced Raman spectroscopy and atomic force microscopy. A model according to Gersten and Nitzan was applied and SERS enhancement factors in the near-IR were calculated for various metal hemi-spheroids. FT-Raman spectra were presented for thin vacuum evaporated films of titanyl phthalocyanine (TiOPc) and vanadyl phthalocyanine (VOPc) prepared on glass substrates held at a range of temperatures during deposition. The frequencies were assigned and different polymorphic forms were apparent. In order to improve the signal intensity, thin films were deposited on metal substrates which produced SERS in the near-IR. The substrates selected for FT-SERS were vacuum evaporated metal island films of copper and gold of 20 nm mass thickness prepared with the glass substrate held at 200...