Raman spectroscopy is a common tool for the qualitative and quantitative chemical analysis of molecules. Although the unique identification of molecules is possible via their vibrational lines, high concentrations (mmol/l) are needed for their nonresonant excitation owing to their low scattering cross section. The intensity of the Raman spectra is amplified by the use of the surface-enhanced Raman scattering (SERS) technique. While the use of silver sols results only in a limited reproducibility of the Raman line intensities, lithographically designed, nanostructured gold surfaces used as SERS-active substrates should, in principle, combine the high sensitivity with better reproducibility. For this purpose, we have produced gratings of gold dots on Si(001) surfaces by means of electron beam lithography. Qualitative and quantitative investigations of crystal violet (CV) performed using nanostructured surfaces give high reproducibility and enhancement of the Raman lines. The substrates are reusable after cleaning; all results presented could be obtained from a single SERS substrate. For the experiments very low laser powers were used.

Here we report on the synthesis, structure, and characterization of the first example of a polyoxopalladate (POP)-based metal-organic framework (MOF). This novel class of materials comprises discrete polyoxo-13-palladate(II) nanocubes [Pd 13 O 8 (AsO 4 ) 8 H 6 ] 8− decorated by four Ba 2+ ions on each of two opposite faces. These secondary building units (SBUs) are linked to each other via rigid linear organic groups, resulting in a stable 3D POP-MOF framework, which exhibits interesting sorption as well as catalytic properties.

To achieve high performance organic field effect transistors (OFETs) with enhanced currents, high switching speeds and improved integration density the channel length L is downscaled to the sub‐micrometer regime. The influence of important scaling parameters on the electrical performance of bottom contact devices is analyzed. High‐mobility oligo‐ and polythiophenes were used as semiconductor, which combine the advantages of highly ordered growth with processibility from solution. Devices with optimized parameters exhibit high switching frequencies beyond 2 MHz. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

No abstract