Adsorption of Large Organic Molecules on Clean and Hydroxylated Rutile TiO2(110) Surfaces

Behavior of large organic molecules equipped with spacer groups (Violet Landers, VL) on the TiO2(110)-(1x1) surfaces is investigated by means of high-resolution scanning tunneling microscopy (STM). Two distinct adsorption geometries are observed. We demonstrate that the molecule adsorption morphology can be alternated by well-controlled STM tip-induced manipulation. It is used to probe the mobility of molecules and reveals locking in one of the analyzed adsorption sites, thus allow to enhance or reduce the mobility along the [001] direction. Field induced hydrogen desorption is used to perform lateral STM manipulation on a hydroxyl-free surface, which provides insight into the influence of surface hydroxyl groups on the molecule behavior. The ability to image with submolecular resolution both the central board and the spacer groups of the VL molecule is demonstrated.