Raman polarization studies of highly oriented organic thin films

• Published in: Journal of Raman spectroscopy Vol. 40; no. 12; pp. 2015 - 2022
• Main Authors: Presser, V., Schuster, B.-E., Casu, M. B., Heinemeyer, U., Schreiber, F., Nickel, K. G., Chassé, T.
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.12.2009
• Subjects: Deposition; diindenoperylene; Dipping; Dominance; Molecular beams; molecular orientation; Molecular structure; organic thin film; Orientation; polarized Raman spectroscopy; Raman spectroscopy; rutile; Thin films
• ISSN: 0377-0486; 1097-4555
• DOI: 10.1002/jrs.2361

In this work we report on the capability of polarized Raman spectroscopy to investigate the structure of thin organic films. Diindenoperylene (DIP) thin films on (1 × 1)‐rutile(110) were prepared via organic molecular beam deposition (OMBD). Raman spectra of DIP thin films showed several strong Raman modes in the wavenumber region from 1200 to 1650 cm−1. The Ag mode at 1284 cm−1 shows two contributions, thereby indicating the coexistence of at least two DIP film structures. Polarized Raman spectroscopy was applied to characterize the molecular orientation and the dominance of the σ‐configuration (i.e. upright standing DIP molecules) was found. Copyright © 2009 John Wiley & Sons, Ltd. Polarized Raman spectroscopy is a powerful tool to investigate the structure of thin organic films. In the present study, diindenoperylene (DIP) thin films on (1 × 1)‐rutile(110) were prepared via organic molecular beam deposition (OMBD). As a result, the coexistence of at least two DIP film structures is indicated because of the contribution of two Raman modes. Polarized Raman spectra used to characterize the actual orientation showed that the DIP molecules are predominantly present in the so‐called σ‐configuration (i.e. upright standing).