@article{HollandMoritzGraupnerMoelleretal.2018,
  author    = {Holland-Moritz, Henry and Graupner, Julia and M{\"o}ller, Wolfhard and Pacholski, Claudia and Ronning, Carsten},
  title     = {Dynamics of nanoparticle morphology under low energy ion irradiation},
  series = {Nanotechnology},
  volume    = {29},
  journal   = {Nanotechnology},
  number    = {31},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {0957-4484},
  doi       = {10.1088/1361-6528/aac36c},
  pages     = {7},
  year      = {2018},
  abstract  = {If nanostructures are irradiated with energetic ions, the mechanism of sputtering becomes important when the ion range matches about the size of the nanoparticle. Gold nanoparticles with diameters of similar to 50 nm on top of silicon substrates with a native oxide layer were irradiated by gallium ions with energies ranging from 1 to 30 keV in a focused ion beam system. High resolution in situ scanning electron microscopy imaging permits detailed insights in the dynamics of the morphology change and sputter yield. Compared to bulk-like structures or thin films, a pronounced shaping and enhanced sputtering in the nanostructures occurs, which enables a specific shaping of these structures using ion beams. This effect depends on the ratio of nanoparticle size and ion energy. In the investigated energy regime, the sputter yield increases at increasing ion energy and shows a distinct dependence on the nanoparticle size. The experimental findings are directly compared to Monte Carlo simulations obtained from iradina and TRI3DYN, where the latter takes into account dynamic morphological and compositional changes of the target.},
  language  = {en}
}
@article{BekirJelkenJungetal.2021,
  author    = {Bekir, Marek and Jelken, Joachim and Jung, Se-Hyeong and Pich, Andrij and Pacholski, Claudia and Kopyshev, Alexey and Santer, Svetlana},
  title     = {Dual responsiveness of microgels induced by single light stimulus},
  series = {Applied physics letters},
  volume    = {118},
  journal   = {Applied physics letters},
  number    = {9},
  publisher = {American Institute of Physics},
  address   = {Melville},
  issn      = {0003-6951},
  doi       = {10.1063/5.0036376},
  pages     = {6},
  year      = {2021},
  abstract  = {We report on the multiple response of microgels triggered by a single optical stimulus. Under irradiation, the volume of the microgels is reversibly switched by more than 20 times. The irradiation initiates two different processes: photo-isomerization of the photo-sensitive surfactant, which forms a complex with the anionic microgel, rendering it photo-responsive; and local heating due to a thermo-plasmonic effect within the structured gold layer on which the microgel is deposited. The photo-responsivity is related to the reversible accommodation/release of the photo-sensitive surfactant depending on its photo-isomerization state, while the thermo-sensitivity is intrinsically built in. We show that under exposure to green light, the thermo-plasmonic effect generates a local hot spot in the gold layer, resulting in the shrinkage of the microgel. This process competes with the simultaneous photo-induced swelling. Depending on the position of the laser spot, the spatiotemporal control of reversible particle shrinking/swelling with a predefined extent on a per-second base can be implemented.},
  language  = {en}
}
@article{SchuermannNagelJuergensenetal.2022,
  author    = {Sch{\"u}rmann, Robin and Nagel, Alessandro and Juergensen, Sabrina and Pathak, Anisha and Reich, Stephanie and Pacholski, Claudia and Bald, Ilko},
  title     = {Microscopic understanding of reaction rates observed in plasmon chemistry of nanoparticle-ligand systems},
  series = {The journal of physical chemistry : C, Nanomaterials and interfaces},
  volume    = {126},
  journal   = {The journal of physical chemistry : C, Nanomaterials and interfaces},
  number    = {11},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {1932-7447},
  doi       = {10.1021/acs.jpcc.2c00278},
  pages     = {5333 -- 5342},
  year      = {2022},
  abstract  = {Surface-enhanced Raman scattering (SERS) is an effective and widely used technique to study chemical reactions induced or catalyzed by plasmonic substrates, since the experimental setup allows us to trigger and track the reaction simultaneously and identify the products. However, on substrates with plasmonic hotspots, the total signal mainly originates from these nanoscopic volumes with high reactivity and the information about the overall consumption remains obscure in SERS measurements. This has important implications; for example, the apparent reaction order in SERS measurements does not correlate with the real reaction order, whereas the apparent reaction rates are proportional to the real reaction rates as demonstrated by finite-difference time-domain (FDTD) simulations. We determined the electric field enhancement distribution of a gold nanoparticle (AuNP) monolayer and calculated the SERS intensities in light-driven reactions in an adsorbed self-assembled molecular monolayer on the AuNP surface. Accordingly, even if a high conversion is observed in SERS due to the high reactivity in the hotspots, most of the adsorbed molecules on the AuNP surface remain unreacted. The theoretical findings are compared with the hot-electron-induced dehalogenation of 4-bromothiophenol, indicating a time dependency of the hot-carrier concentration in plasmon-mediated reactions. To fit the kinetics of plasmon-mediated reactions in plasmonic hotspots, fractal-like kinetics are well suited to account for the inhomogeneity of reactive sites on the substrates, whereas also modified standard kinetics model allows equally well fits. The outcomes of this study are on the one hand essential to derive a mechanistic understanding of reactions on plasmonic substrates by SERS measurements and on the other hand to drive plasmonic reactions with high local precision and facilitate the engineering of chemistry on a nanoscale.},
  language  = {en}
}