Solvent effects on chain orientation and interchain π-interaction in conjugated polymer thin films: Direct measurements of the air and substrate interfaces by near-edge X-ray absorption spectroscopy

10.1002/adma.200601285Advanced Materials192215-221ADVM

NEXAFS Investigations on Highly-Ordered Ultrathin Films of DMe-DCNQI on Single Crystal Surfaces

DMe-DCNQI forms highly-ordered ultrathin films on various single crystal surfaces. NEXAFS reveals flat lying molecules for a l investigated film thicknesses (up to 40 layers) on nearly all substrates under investigation (Ag(111). Ag(l00), Cu(100), Cu(111)). The Cls and Nls NEXAFS spectra of these condensed layers show several very sharp resonances. The comparison with the quinoide molecules TCNQ and DMe-BQ shows similarities, but the electronic structure is too complicated to be interpreted m terms of a building block scheme. NEXAFS data of related charge transfer salts consist of fewer and much broader resonances in accordance with the more delocalized electronic structure of the 'quasimetaUie' salts

Beamline 1511 at MAX II, capabilities and performance

The new undulator beamline 1511 at MAX-lab, now under commissioning, has been optimized for X-ray emission and photoelectron spectroscopies. Using an SX-700 high flux monochromator the accessible photon energy range is from 90 eV to about 1500 eV. The performance of the undulator agrees very well with the specifications, as shown by measurements using a photodiode. The energy resolution of the monochromator has been checked using absorption measurements in a gas cell. It was found to meet the expectations and exceeds a resolving power of 10 000 at 244 eV. The photon flux as a function of energy has been recorded as well and gives a maximum flux of 3×1013 photons/s/100 mA/0.1% BW. Beamlines 1511 and 1411 will be the first synchrotron beamlines making use of a so-called beam waist phenomenon, known from laser physics. We show results of ray-tracing calculations to determine the ultimate spot size on the sample location. The endstations to be used at this new beamline and their capabilities will be discussed as an example of the future use of this facility