Isotope Engineered Fluorinated Single and Bilayer Graphene: Insights into Fluorination Selectivity,Stability, and Defect Passivation |
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Authors: | Mukesh Kumar Thakur Golam Haider Farjana J Sonia Jan Plšek Alvaro Rodriguez Vipin Mishra Jaganandha Panda Ondrej Gedeon Martin Mergl Oleksandr Volochanskyi Václav Valeš Otakar Frank Jana Vejpravova Martin Kalbáč |
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Affiliation: | 1. J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 2155/3, 18200 Prague 8, Czech Republic;2. Department of Glass and Ceramics, University of Chemistry and Technology, Prague, Technická 5, 16628 Prague 6, Czech Republic;3. Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 12116 Prague 2, Czech Republic |
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Abstract: | Tailoring the physicochemical properties of graphene through functionalization remains a major interest for next-generation technological applications. However, defect formation due to functionalization greatly endangers the intrinsic properties of graphene, which remains a serious concern. Despite numerous attempts to address this issue, a comprehensive analysis has not been conducted. This work reports a two-step fluorination process to stabilize the fluorinated graphene and obtain control over the fluorination-induced defects in graphene layers. The structural, electronic and isotope-mass-sensitive spectroscopic characterization unveils several not-yet-resolved facts, such as fluorination sites and C F bond stability in partially-fluorinated graphene (F-SLG). The stability of fluorine has been correlated to fluorine co-shared between two graphene layers in fluorinated-bilayer-graphene (F-BLG). The desorption energy of co-shared fluorine is an order of magnitude higher than the C F bond energy in F-SLG due to the electrostatic interaction and the inhibition of defluorination in the F-BLG. Additionally, F-BLG exhibits enhanced light–matter interaction, which has been utilized to design a proof-of-concept field-effect phototransistor that produces high photocurrent response at a time <200 µs. Thus, the study paves a new avenue for the in-depth understanding and practical utilization of fluorinated graphenic carbon. |
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Keywords: | defect passivation fluorination graphene in situ Raman spectroscopy isotopes ultra-fast phototransistors |
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