Highly Ordered Single Domain Peri-Tetracene Monolayers on Ag(110)

The on-surface reaction of 1,1'-bitetracene (Bi4A) to peri-tetracene (tetrabenzo[bc,ef,kl,no]coronene) (4-PA) on Cu(110) and Ag(110) is studied by photoemission, scanning tunneling microscopy (STM) and low energy electron diffraction (LEED). Density functional theory (DFT) computations suggest that the Ag(110) substrate is well suited for the formation of large-area 4-PA monolayers with a preferential adsorption alignment of 4-PA molecules along the [110] direction. The experiments confirm the formation of 4-PA and presence of large highly ordered 4-PA domains. Two distinct phases emerge, growing seamlessly over large areas and even spanning step edges. Evidence for charge transfer from the substrate to the molecule was found, resulting in a filling of the lowest unoccupied molecular orbital (LUMO) of 4-PA.