Optically detected magnetic resonance as a tool to study the morphology ofperylene-derivative thin film

Perylene tetracarboxylic acid diimide (PTCDI) thin films, with thickness of similar to 300 nm, were coated on a glass substrate by vapor deposition. T he morphology of the molecules with respect to the substrate and its influe nce on the magneto-optical properties of the thin films were examined by th e utilization of optically detected magnetic resonance (ODMR) spectroscopy. A typical ODMR spectrum of the studied films contains half- and full-field triplet resonance transitions. The simulation of the triplet line-shape wa s done by the utilization of spin-Hamiltonian, including Zeemnn and anisotr opic dipole-dipole interactions. The results have revealed that the morphol ogy is consistent with a Gaussian distribution of the molecular planes, cen tered parallel to the substrate, with full width at half maximum of 22 degr ees. (C) 1999 Elsevier Science B.V. All rights reserved.