Quantitative Analysis Of The Electronic Decoupling Of An Organic Semiconductor Molecule At A Metal Interface By A Monolayer Of Hexagonal Boron Nitride

The adsorption geometry, the electronic properties, and the adsorption energy of the prototype organic molecule 3,4,9,10-perylene tetracarboxylic dianhydride (PTCDA) on a monolayer of hexagonal boron nitride (hBN) grown on the Cu(111) surface were determined experimentally. The perylene core is at a large height of 3.37 angstrom and only a minute downward displacement of the functional anhydride groups (0.07 angstrom) occurs, yielding adsorption heights that agree with the sum of the involved van der Waals radii. Thus, already a single hBN layer leads to a decoupled (physisorbed) molecule, contrary to the situation on the bare Cu(111) surface.