Templated microwave synthesis of luminescent carbon nanofibers. Issue 23 (6th April 2018)

• Record Type: Journal Article
• Authors: Deeney, Clara; Wang, Suxiao; Belhout, Samir A.; Gowen, Aoife; Rodriguez, Brian J.; Redmond, Gareth; Quinn, Susan J.
• Is Part Of: RSC advances. Volume 8:Issue 23(2018)
• Page Start: 12907
• Page End: 12917
• Publication Date: 2018-04-06
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c7ra13383a
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : This work describes the preparation of luminescent carbon nanofibers by template-assisted microwave pyrolysis of environmentally friendly precursors in aqueous solution. Abstract : Carbon based nanomaterials offer the potential to provide solutions to key technological challenges. This work describes the preparation of luminescent carbon nanofibers by template-assisted microwave pyrolysis of environmentally friendly precursors, citric acid and polyethyleneimine, in aqueous solution. SEM reveals a dense forest of vertically aligned cylindrical carbon nanofibers with an average diameter of ca. 200 nm, which are shown by TEM to be amorphous. Compositional analysis indicated the incorporation of amino and pyrrolic nitrogen, and carbon–oxygen moieties. These species contribute to UV light absorption with an absorption shoulder and tail towards visible wavelengths. UV excitation gave visible (blue) emission at ca. 450 nm with a quantum yield of ca. 5%; emission decay under pulsed excitation was predominantly mono-exponential with a lifetime of ca. 1 ns. The emission maximum is largely excitation wavelength independent suggesting the involvement of citrazinic acid-type functionalities in the fiber photophysics. Reversible pH-dependent excitation and emission behaviour was observed, with maximum emission at ca. pH 7. Nanofiber emission was also quenched in aqueous solutions of metal cations, in a concentration-dependent manner. Single nanofiber emission intensity was quite stable under continuous excitation permitting single fiber quenching-based metal ion detection whereby a significant (>90%) and prompt (sub-10 s) quenching was observed upon exposure to sub-millimolar Fe(iii ) solutions. The introduction of these new 1D luminescent carbon nanofibers offers the potential for exciting developments across a range of applications.