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The electronic properties of polycrystalline 6,13-Bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) was probed by inner-shell spectroscopies such as near-edge X-ray absorption fine structure (NEXAFS) spectroscopy and electron emission spectroscopy at the SiK-edge. Although the lowest unoccupied molecular orbital (LUMO) near the Fermi level is mainly on the acene unit, a small LUMO peak was observed in Si 1s NEXAFS spectra. Angle-dependent NEXAFS spectra indicate that a well-ordered structure is produced in the polycrystalline TIPS-pentacene. It was demonstrated that randomly oriented small single-crystal grains can be aligned by rubbing the powder sample. [ABSTRACT FROM AUTHOR]

We have developed photoelectron emission microscope (PEEM) system with excitation of linearly polarized synchrotron X-rays at 30° incidence angle arrangement. The morphology, electronic structure, orientation for P3HT:PCBM hybrid films have been investigated using the PEEM instrument. The sulphur 1s near-edge X-ray-absorption fine structure (NEXAFS) spectra at micro-domains were obtained, where sulphur atoms of thiophene ring were detected. The nature and symmetry in the S 1s excitations of P3HT model cluster were elucidated by DFT calculations that we performed to assign resonant peaks in absorption spectra. We demonstrate that the orientation at micro-domains can be deduced from photon-energy dependencies of PEEM images. [ABSTRACT FROM AUTHOR]