Konfokales Raman-Mikroskop

• Fachliche Zuordnung: Chemische Festkörper- und Oberflächenforschung
• Förderung: Förderung in 2015
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 270227447

• Erstellungsjahr: 2019

Zusammenfassung der Projektergebnisse

Ever since 2015, the combination of Raman spectroscopy and microscopy turned into an extremely valuable tool in our multi-faceted investigation of synthetic carbon allotropes. In particular, we employed the combination of them in a statistical way in two different areas of synthetic carbon allotropes: one-dimensional single-walled carbon nanotubes and twodimensional graphene, as well as two-dimensional inorganic materials. In the context of one-dimensional single-walled carbon nanotubes, the major objective was to explore chiral selectivity, diameter selectivity, and electronic selectivity. Chiral selectivity was successfully demonstrated in analyzing the corresponding RBM-modes in the range from 250 to 300 cm-1. In contrast, insights into electronic selectivity came from a closer look at the G- and 2D-modes at around 1590 and 2600 cm-1, respectively. In short, we demonstrated the chiral selectivity in a number of mechanically interlocked single-walled carbon nanotubes using electron donating porphyrins and π-extended tetrathiafulvalene as well as with a series of water-soluble perylenediimides. Important is the fact that the latter helped to individualize and stabilize singlewalled carbon nanotubes in aqueous media. Electronic selectivity is correlated with, for example, the partial oxidation of singlewalled carbon nanotubes and a partial reduction of perylenediimides, even in the ground state. Related to two-dimensional graphene we realized two different objectives. On one hand, the degree of exfoliation, that is, single layer graphene by inspecting the 2D-mode in the range of 2560 and 2700cm-1 and the relative ratio between the G- and 2D-modes. In this context, we differentiated not only between single layer and multilayer graphene flakes but also between turbostatic and fully individual graphene flakes. FWHMs of around 65 cm-1 confirm the presence of turbostratic graphene flakes. On the other hand, we looked into p- or n-doping by means of molecular electron acceptors and donors, respectively, following up- or down-shifts of the G- and 2D-modes. For example, in the case of electron donating phthalocyanines both modes down-shift from which we concluded n-doping of graphene flakes. In stark contrast, up-shifts were observed when using electron accepting perylenediimides resulting in p-doping of the graphene flakes. As a complement, we probed graphene oxide featuring different degrees of oxidation and hydrogenated graphene flakes.

Projektbezogene Publikationen (Auswahl)

• Assigning Electronic States in Carbon Nanodots. Advanced Functional Materials, 26(44), 7975-7985.
  Strauss, Volker; Kahnt, Axel; Zolnhofer, Eva M.; Meyer, Karsten; Maid, Harald; Placht, Christian; Bauer, Walter; Nacken, Thomas J.; Peukert, Wolfgang; Etschel, Sebastian H.; Halik, Marcus & Guldi, Dirk M.
  
• Bulbous gold–carbon nanodot hybrid nanoclusters for cancer therapy. Journal of Materials Chemistry B, 5(43), 8591-8599.
  Hasenöhrl, Dominik H.; Saha, Avishek; Strauss, Volker; Wibmer, Leonie; Klein, Stefanie; Guldi, Dirk M. & Hirsch, Andreas
  
• Low-Dimensional Carbon Allotropes: Ground- and Excited-State Charge Transfer with NIR-Absorbing Heptamethine Cyanine. Chem, 3(1), 164-173.
  Roth, Alexandra; Schierl, Christoph; Ferrer-Ruiz, Andrés; Minameyer, Martin; Rodríguez-Pérez, Laura; Villegas, Carmen; Herranz, Ma Ángeles; Martín, Nazario & Guldi, Dirk M.
  
• n- versus p-doping of graphite: what drives its wet-chemical exfoliation?. Nanoscale, 9(32), 11632-11639.
  Wang, Bingzhe; Engelhardt, Verena; Roth, Alexandra; Faust, Rüdiger & Guldi, Dirk M.
  
• Excitons and Trions in One‐Photon‐ and Two‐Photon‐Excited MoS2: A Study in Dispersions. Advanced Materials, 30(12).
  Wibmer, Leonie; Lages, Sebastian; Unruh, Tobias & Guldi, Dirk M.
  
• Exfoliation of Graphene by Dendritic Water‐Soluble Zinc Phthalocyanine Amphiphiles in Polar Media. Chemistry – A European Journal, 24(70), 18696-18704.
  Methfessel, Christian D.; Volland, Michel; Brunner, Kristin; Wibmer, Leonie; Hahn, Uwe; de la Torre, Gema; Torres, Tomás; Hirsch, Andreas & Guldi, Dirk M.
  
• Interfacing porphyrins and carbon nanotubes through mechanical links. Chemical Science, 9(33), 6779–6784.
  de Juan-Fernández, Leire; Münich, Peter W.; Puthiyedath, Arjun; Nieto-Ortega, Belén; Casado, Santiago; Ruiz-González, Luisa; Pérez, Emilio M. & Guldi, Dirk M.
  
• Tuning the Carbon Nanotube Selectivity: Optimizing Reduction Potentials and Distortion Angles in Perylenediimides. Journal of the American Chemical Society, 140(16), 5427-5433.
  Münich, Peter W.; Schierl, Christoph; Dirian, Konstantin; Volland, Michel; Bauroth, Stefan; Wibmer, Leonie; Syrgiannis, Zois; Clark, Timothy; Prato, Maurizio & Guldi, Dirk M.
  
• Nanographene favors electronic interactions with an electron acceptor rather than an electron donor in a planar fused push–pull conjugate. Nanoscale, 11(3), 1437-1441.
  Volland, Michel; Zhou, Ping; Wibmer, Leonie; Häner, Robert; Decurtins, Silvio; Liu, Shi-Xia & Guldi, Dirk M.