Understanding the optical properties of doped and undoped 9-armchair graphene nanoribbons in dispersion

• Verfasst von: Lindenthal, Sebastian [VerfasserIn]
• Verfasst von: Fazzi, Daniele [VerfasserIn]
• Verfasst von: Zorn, Nicolas [VerfasserIn]
• Verfasst von: El Yumin, Abdurrahman Ali [VerfasserIn]
• Verfasst von: Settele, Simon [VerfasserIn]
• Verfasst von: Weidinger, Britta [VerfasserIn]
• Verfasst von: Blasco, Eva [VerfasserIn]
• Verfasst von: Zaumseil, Jana [VerfasserIn]
• Titel: Understanding the optical properties of doped and undoped 9-armchair graphene nanoribbons in dispersion
• Verf.angabe: Sebastian Lindenthal, Daniele Fazzi, Nicolas F. Zorn, Abdurrahman Ali El Yumin, Simon Settele, Britta Weidinger, Eva Blasco, and Jana Zaumseil
• E-Jahr: 2023
• Jahr: September 26, 2023
• Umfang: 13 S.
• Illustrationen: Illustrationen
• Fussnoten: Online veröffentlicht: 11. September 2023 ; Gesehen am 25.10.2023
• Titel Quelle: Enthalten in: American Chemical SocietyACS nano
• Ort Quelle: Washington, DC : Soc., 2007
• Jahr Quelle: 2023
• Band/Heft Quelle: 17(2023), 18 vom: Nov., Seite 18240-18252
• ISSN Quelle: 1936-086X
• DOI: doi:10.1021/acsnano.3c05246
• Datenträger: Online-Ressource
• Sprache: eng
• Bibliogr. Hinweis: Forschungsdaten: Lindenthal, Sebastian: Optical properties of doped and undoped 9-armchair graphene nanoribbons [data]
• K10plus-PPN: 1867620057

Abstract

Graphene nanoribbons are one-dimensional stripes of graphene with width- and edge-structure-dependent electronic properties. They can be synthesized bottom-up in solution to obtain precise ribbon geometries. Here we investigate the optical properties of solution-synthesized 9-armchair graphene nanoribbons (9-aGNRs) that are stabilized as dispersions in organic solvents and further fractionated by liquid cascade centrifugation (LCC). Absorption and photoluminescence spectroscopy reveal two near-infrared absorption and emission peaks whose ratios depend on the LCC fraction. Low-temperature single-nanoribbon photoluminescence spectra suggest the presence of two different nanoribbon species. Based on density functional theory (DFT) and time-dependent DFT calculations, the lowest energy transition can be assigned to pristine 9-aGNRs, while 9-aGNRs with edge-defects, caused by incomplete graphitization, result in more blue-shifted transitions and higher Raman D/G-mode ratios. Hole doping of 9-aGNR dispersions with the electron acceptor F4TCNQ leads to concentration dependent bleaching and quenching of the main absorption and emission bands and the appearance of red-shifted, charge-induced absorption features but no additional emission peaks, thus indicating the formation of polarons instead of the predicted trions (charged excitons) in doped 9-aGNRs.