@phdthesis{Buchheit2022,
  author    = {Buchheit, Roman},
  title     = {Dielectric layers of hybrid Gold@Polystyrene Nanoparticle Inks},
  organization    = {INM - Leibniz-Institut f{\"u}r Neue Materialien},
  doi       = {10.22028/D291-37125},
  institution = {Structure Formation},
  school    = {Universit{\"a}t des Saarlandes},
  year      = {2022},
  abstract  = {A new type of hybrid dielectric based on nanoparticles with gold cores with diameters of 2.9-8.2 nm and covalently bound thiol-terminated polystyrene shells (Mn = 5000 Da and Mn = 11000 Da) is introduced. Particle dispersions were spin coated as dielectric films of thin film capacitors. The metal contents were 5-31 vol\%, and the particles packed randomly or in face-centred-cubic superstructures, mainly depending on the polymer shell. Films with 9 vol\% metal and 2.9 nm cores had dielectric constants of 98@1 Hz. Small angle X-ray scattering, transmission electron microscopy, and impedance spectroscopy indicate that classical random capacitor-resistor network models partially describe the hybrid materials. The covalently attached polymer shells enabled higher metal contents than in conventional nanocomposites without the risk of conductive breakdown. Dielectric properties depended on the metal content and the core size, but not on the network structure. The frequency-dependent dielectric polarization mainly takes place at the interfacial areas, but is not considered in the classical models. Smaller core sizes increased internal interfacial areas at comparable metal fractions by 46 \%, resulting in 40 \% larger dielectric constants in agreement with the Maxwell-Wagner-Sillars model. Inkjet-printed capacitors were prepared with a capacitance of 2.0±0.1 nF@10 kHz over an area of 0.79 mm² on rigid substrates; they retained their functionality over 3500 bending cycles on flexible substrates.},
  language  = {en}
}