@article{KogikoskiJuniorDuttaBald2021,
  author    = {Kogikoski Junior, Sergio and Dutta, Anushree and Bald, Ilko},
  title     = {Spatial separation of plasmonic hot-electron generation and a hydrodehalogenation reaction center using a DNA wire},
  series = {ACS nano},
  volume    = {15},
  journal   = {ACS nano},
  number    = {12},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {1936-0851},
  doi       = {10.1021/acsnano.1c09176},
  pages     = {20562 -- 20573},
  year      = {2021},
  abstract  = {Using hot charge carriers far from a plasmonic nanoparticle surface is very attractive for many applications in catalysis and nanomedicine and will lead to a better understanding of plasmon-induced processes, such as hot-charge-carrier- or heat-driven chemical reactions. Herein we show that DNA is able to transfer hot electrons generated by a silver nanoparticle over several nanometers to drive a chemical reaction in a molecule nonadsorbed on the surface. For this we use 8-bromo-adenosine introduced in different positions within a double-stranded DNA oligonucleotide. The DNA is also used to assemble the nanoparticles into nanoparticles ensembles enabling the use of surface-enhanced Raman scattering to track the decomposition reaction. To prove the DNA-mediated transfer, the probe molecule was insulated from the source of charge carriers, which hindered the reaction. The results indicate that DNA can be used to study the transfer of hot electrons and the mechanisms of advanced plasmonic catalysts.},
  language  = {en}
}
@article{KogikoskiJuniorTapioEdlervonZanderetal.2021,
  author    = {Kogikoski Junior, Sergio and Tapio, Kosti and Edler von Zander, Robert and Saalfrank, Peter and Bald, Ilko},
  title     = {Raman enhancement of nanoparticle dimers self-assembled using DNA origami nanotriangles},
  series = {Molecules : a journal of synthetic chemistry and natural product chemistry / Molecular Diversity Preservation International},
  volume    = {26},
  journal   = {Molecules : a journal of synthetic chemistry and natural product chemistry / Molecular Diversity Preservation International},
  number    = {6},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {1420-3049},
  doi       = {10.3390/molecules26061684},
  pages     = {18},
  year      = {2021},
  abstract  = {Surface-enhanced Raman scattering is a powerful approach to detect molecules at very low concentrations, even up to the single-molecule level. One important aspect of the materials used in such a technique is how much the signal is intensified, quantified by the enhancement factor (EF). Herein we obtained the EFs for gold nanoparticle dimers of 60 and 80 nm diameter, respectively, self-assembled using DNA origami nanotriangles. Cy5 and TAMRA were used as surface-enhanced Raman scattering (SERS) probes, which enable the observation of individual nanoparticles and dimers. EF distributions are determined at four distinct wavelengths based on the measurements of around 1000 individual dimer structures. The obtained results show that the EFs for the dimeric assemblies follow a log-normal distribution and are in the range of 10(6) at 633 nm and that the contribution of the molecular resonance effect to the EF is around 2, also showing that the plasmonic resonance is the main source of the observed signal. To support our studies, FDTD simulations of the nanoparticle's electromagnetic field enhancement has been carried out, as well as calculations of the resonance Raman spectra of the dyes using DFT. We observe a very close agreement between the experimental EF distribution and the simulated values.},
  language  = {en}
}
@article{DuttaSchuermannKogikoskiJunioretal.2021,
  author    = {Dutta, Anushree and Sch{\"u}rmann, Robin and Kogikoski Junior, Sergio and Mueller, Niclas S. and Reich, Stephanie and Bald, Ilko},
  title     = {Kinetics and mechanism of plasmon-driven dehalogenation reaction of brominated purine nucleobases on Ag and Au},
  series = {ACS catalysis / American Chemical Society},
  volume    = {11},
  journal   = {ACS catalysis / American Chemical Society},
  number    = {13},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {2155-5435},
  doi       = {10.1021/acscatal.1c01851},
  pages     = {8370 -- 8381},
  year      = {2021},
  abstract  = {Plasmon-driven photocatalysis is an emerging and promising application of noble metal nanoparticles (NPs). An understanding of the fundamental aspects of plasmon interaction with molecules and factors controlling their reaction rate in a heterogeneous system is of high importance. Therefore, the dehalogenation kinetics of 8-bromoguanine (BrGua) and 8-bromoadenine (BrAde) on aggregated surfaces of silver (Ag) and gold (Au) NPs have been studied to understand the reaction kinetics and the underlying reaction mechanism prevalent in heterogeneous reaction systems induced by plasmons monitored by surface enhanced Raman scattering (SERS). We conclude that the time-average constant concentration of hot electrons and the time scale of dissociation of transient negative ions (TNI) are crucial in defining the reaction rate law based on a proposed kinetic model. An overall higher reaction rate of dehalogenation is observed on Ag compared with Au, which is explained by the favorable hot-hole scavenging by the reaction product and the byproduct. We therefore arrive at the conclusion that insufficient hole deactivation could retard the reaction rate significantly, marking itself as rate-determining step for the overall reaction. The wavelength dependency of the reaction rate normalized to absorbed optical power indicates the nonthermal nature of the plasmon-driven reaction. The study therefore lays a general approach toward understanding the kinetics and reaction mechanism of a plasmon-driven reaction in a heterogeneous system, and furthermore, it leads to a better understanding of the reactivity of brominated purine derivatives on Ag and Au, which could in the future be exploited, for example, in plasmon-assisted cancer therapy.},
  language  = {en}
}