TY - JOUR A1 - Pavlenko, E. S. A1 - Sander, M. A1 - Mitzscherling, Steffen A1 - Pudell, J. A1 - Zamponi, F. A1 - Rössle, M. A1 - Bojahr, A. A1 - Bargheer, M. T1 - Azobenzene – functionalized polyelectrolyte nanolayers as ultrafast optoacoustic transducers JF - Nanoscale N2 - We introduce azobenzene-functionalized polyelectrolyte multilayers as efficient, inexpensive optoacoustic transducers for hyper-sound strain waves in the GHz range. By picosecond transient reflectivity measurements we study the creation of nanoscale strain waves, their reflection from interfaces, damping by scattering from nanoparticles and propagation in soft and hard adjacent materials like polymer layers, quartz and mica. The amplitude of the generated strain ε∼5×10−4 is calibrated by ultrafast X-ray diffraction. KW - Picosecond acoustic KW - Ultrafast optoacoustic KW - Nanolayer KW - Polyelectrolyte PY - 2016 DO - https://doi.org/10.1039/c6nr01448h SN - 2040-3364 SN - 2040-3372 VL - 8 IS - 27 SP - 13297 EP - 13302 AN - OPUS4-37079 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mitzscherling, Steffen A1 - Cui, Q. A1 - Koopman, W. A1 - Bargheer, M. T1 - Dielectric function of two-phase colloid-polymer nanocomposite JF - Physical chemistry, chemical physics N2 - The plasmon resonance of metal nanoparticles determines their optical response in the visible spectral range. Many details such as the electronic properties of gold near the particle surface and the local environment of the particles influence the spectra. We show how the cheap but highly precise fabrication of composite nanolayers by spin-assisted layer-by-layer deposition of polyelectrolytes can be used to investigate the spectral response of gold nanospheres (GNS) and gold nanorods (GNR) in a self-consistent way, using the established Maxwell–Garnett effective medium (MGEM) theory beyond the limit of homogeneous media. We show that the dielectric function of gold nanoparticles differs from the bulk value and experimentally characterize the shape and the surrounding of the particles thoroughly by SEM, AFM and ellipsometry. Averaging the dielectric functions of the layered surrounding by an appropriate weighting with the electric field intensity yields excellent agreement for the spectra of several nanoparticles and nanorods with various cover-layer thicknesses. PY - 2015 DO - https://doi.org/10.1039/c5cp04326c SN - 1463-9076 SN - 1463-9084 VL - 17 IS - 44 SP - 29465 EP - 29474 PB - The Royal Soc. of Chemistry CY - Cambridge AN - OPUS4-34920 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -