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

Perylene tetracarboxylic acid diimide (PTCDI) thin films, with thickness of ∼300 nm, were coated on a glass substrate by vapor deposition. The morphology of the molecules with respect to the substrate and its influence on the magneto-optical properties of the thin films were examined by the 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 was done by the utilization of spin-Hamiltonian, including Zeeman and anisotropic dipole–dipole interactions. The results have revealed that the morphology is consistent with a Gaussian distribution of the molecular planes, centered parallel to the substrate, with full width at half maximum of 22°.