Growth of anthracene derivative thin films with a π-stacking structure

Abstract

The main purpose of this study is to grow an organic thin film consisting of aromatic molecules with enhanced π-conjugations. For this purpose, an anthracene derivative, 9,10-bis (methylthio) anthracene, was deposited on a CaF2∕Si(111) substrate using a hot-wall epitaxy technique. The crystal structure of this anthracene derivative consists of molecular stacks with a face-to-face configuration due to the sulfur-sulfur interactions between neighboring molecules, which enhances π-electron conjugation. The hot-wall epitaxy technique made precise control of the growth conditions possible. Atomic force microscopy and x-ray diffraction measurements demonstrated that a polycrystalline thin film with the molecules in the face-to-face configuration was obtained, and that, depending on the growth conditions, the thin-film structure was controllable.