Growth of ordered thin films of tris(phenylquinoxaline) by organic molecular beam deposition

We report about organic molecular beam deposition of 1,3,5-tris[(6,7-dimethyl-3-phenyl)quinoxaline-2-yl]benzene (Me-TPQ), a molecule with very promising electron transporting properties. We have studied the evaporation conditions in order to achieve control over the molecular order in the grown layer. Especially the choice of the substrate has been found to be crucial. Type and degree of molecular order have been determined by X-ray diffraction measurements. Absorption and photoluminescence spectra of the grown films have been recorded in order to detect any influence of the molecular packing on the optical properties. We demonstrate that it is possible to grow ordered thin films of Me-TPQ by proper choice of the deposition conditions.