Role of oxygen incorporation in electronic properties of rubrene films

摘要

The electronic properties of rubrene films exposed to oxygen have been studied by photoemissionnand x-ray absorption spectroscopies. Oxygen incorporation causes the highest occupied molecularnorbital of rubrene to shift to a u00041.0 eV deep level due to chemical bonds formed by the oxygennatoms with the carbon atoms within the tetracene backbone of rubrene molecules. Deformation ofnthe molecular backbone induced by the C–O bonds destroys the delocalized nature of the molecularnorbitals. The oxidized rubrene molecules in a single crystal are proposed to act as point defects thatndisturb the long-range periodicity and produce localized acceptor states. © 2010 American Institutenof Physics. u0005doi:10.1063/1.3466914