@article{KarageorgievNeherSchulzetal.2005,
  author    = {Karageorgiev, Peter and Neher, Dieter and Schulz, Burkhard and Stiller, Burkhard and Pietsch, Ullrich and Giersig, Michael and Brehmer, Ludwig},
  title     = {From anisotropic photo-fluidity towards nanomanipulation in the optical near-field},
  issn      = {1476-1122},
  year      = {2005},
  abstract  = {An increase in random molecular vibrations of a solid owing to heating above the melting point leads to a decrease in its long-range order and a loss of structural symmetry. Therefore conventional liquids are isotropic media. Here we report on a light-induced isothermal transition of a polymer film from an isotropic solid to an anisotropic liquid state in which the degree of mechanical anisotropy can be controlled by light. Whereas during irradiation by circular polarized light the film behaves as an isotropic viscoelastic fluid, it shows considerable fluidity only in the direction parallel to the light field vector under linear polarized light. The fluidization phenomenon is related to photoinduced motion of azobenzene-functionalized molecular units, which can be effectively activated only when their transition dipole moments are oriented close to the direction of the light polarization. We also describe here how the photofluidization allows nanoscopic elements of matter to be precisely manipulated},
  language  = {en}
}
@article{JaroszQuinnStephanetal.2005,
  author    = {Jarosz, Grazyna and Quinn, P. D. and Stephan, Niels and Brehmer, Ludwig},
  title     = {Dielectric properties of zinc phthalocyanine thin films : effects of annealing in air and in N-2},
  issn      = {0040-6090},
  year      = {2005},
  abstract  = {This work presents the effects of ambient conditions, in particular oxygen and humidity, on the dielectric spectra of thin zinc phthalocyanine (ZnPc) films equipped with interdigitated electrodes and the effect of annealing in dry N-2 or in ambient air. The measurements were performed in the frequency range 10(-2)-10(5) Hz. The results indicate that the electric properties of ZnPc films are not only affected by oxygen but also by water vapour the presence of which always leads to the drop in alternating current conductance (ac-conductance). Moreover, at room temperature, the ac-conductance of ZnPc films previously exposed to air exhibits a reversible change with humidity, which makes these films attractive for humidity sensing applications. (C) 2004 Elsevier B.V. All rights reserved},
  language  = {en}
}
@article{DimitrievSmertenkoStilleretal.2005,
  author    = {Dimitriev, O. P. and Smertenko, P. S. and Stiller, Burkhard and Brehmer, Ludwig},
  title     = {Polyaniline-transition metal salt complexes: insight into formation mechanisms},
  issn      = {0379-6779},
  year      = {2005},
  abstract  = {Two basic morphologies of emeraldine base of polyaniline-transition metal salt complex films cast from N- methylpyrrolidinone solutions are described. The first morphology consists of grains and the other consists of loose aggregates, respectively. The correlation of the film morphology with formation of precipitate in the complex solution, kinetics of solvent evaporation from the cast film, amount of solvent entrapped in the film, film conductivity, and IR absorption spectra is shown. Two different mechanisms of the complex formation as a result of competition in the polymer- inorganic salt-solvent trio interactions are discussed; the first mechanism results in folding of macromolecules into compact coils being then a core of grains in the complex films, and the second mechanism leads to blending of the polymer chains with solvent giving rise to formation of loose aggregates. (c) 2005 Elsevier B.V. All rights reserved},
  language  = {en}
}
@book{SmertenkoFenenkoBrehmeretal.2005,
  author    = {Smertenko, P. and Fenenko, L. and Brehmer, Ludwig and Schrader, Sigurd},
  title     = {Differential approach to the study of integral characteristics in polymer films},
  year      = {2005},
  abstract  = {The differential approach is based on the determination of dimensionless differential slope, for instance, of current-voltage characteristics (IVC), I=f(V). This slope (a) is given by formula alpha=d(lgI)/d(lgV). With such definition the ranges of constancy of the a(V) dependency correspond to the part of IVC characterized by the power behaviour (I similar to V-alpha). The differential slope of alpha(V) dependency gamma = d(lg alpha)/dlgV determines the exponent behaviour of curve (I similar to exp {eV(y)/kT}). Processing by the differential approach of the investigated theoretical or experimental characteristics permits us to determine the peculiarity of charge flow mechanisms, temperature behaviour of conductivity, etc. The theoretical base and some applications of differential approach to the investigation of the current-voltage, temperature and degradation characteristics of the polyaniline and poly(p- phenilenevinilene) based structures have been shown. (c) 2005 Elsevier B.V. All rights reserved},
  language  = {en}
}
@book{MuzikanteFonavsBrehmeretal.2005,
  author    = {Muzikante, I. and Fonavs, E. and Brehmer, Ludwig and Stiller, Burkhard},
  title     = {Photoinuced phenomena in corona poled polar organic films},
  year      = {2005},
  abstract  = {Organic materials have received considerable attention because of their large dipole moments and optical nonlinearities. The optically induced switching of material properties is important for studying the optoelectronic effects including second harmonic generation. Organic materials for photonic applications contain chromophore dipole which consist of acceptor and donor groups bridged by a delocalized pi-electron system. Both theoretical and experimental data show a reversible highly dipolar photoinduced intra molecular charge transfer in betaine type molecules accompanied by change of the sign and the value of the dipole moment. The arrangement of polar molecules in films is studied both by atom force microscopy and surface potential measurements. To understand the photo response of these materials, their spectroscopic and electrical properties are studied. The morphology and photoinduced surface potential switching of the self-assembled monolayers and polymer films are investigated. (c) 2005 Elsevier B.V. All rights reserved},
  language  = {en}
}
@article{JaroszSignerskiBrehmer2006,
  author    = {Jarosz, Grazyna and Signerski, Ryszard and Brehmer, Ludwig},
  title     = {On dielectric spectra of thin copper phthalocyanine films},
  issn      = {0040-6090},
  doi       = {10.1016/j.tsf.2006.02.035},
  year      = {2006},
  abstract  = {The work presents low signal dielectric spectra of gold/copper phthalocyanine/magnesium and gold/copper phthalocyanine/gold sandwich systems in the 25 Hz-1 MHz frequency range. The performed analysis enables us to distinguish the electrode resistance and the lattice polarization from processes related with electric transport, such as charge carrier relaxation at space charge region of a barrier and charge carrier injection in dielectric response.},
  language  = {en}
}