Electronic Structure of Nitrogen-Doped Graphene in the Ground and Core-Excited States from First-Principles Simulations
2015 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 119, no 29, 16660-16666 p.Article in journal (Refereed) Published
We have calculated the N 1s near-edge X-ray absorption fine structure (NEXAFS) spectra of nitrogen-doped monolayer graphene (NG) using density functional theory (DFT) with the equivalent core hole approximation. The hexavacancy (6V) defect and its dependence on the nitrogen-doping concentration have been analyzed in detail via both N 1s -> pi* and N 1s -> sigma* transitions. The NEXAFS spectra are sensitive to the doping concentration of N in the pi* region: diluted doping weakens the main pi* peak and smears the oscillations in this region. The vacancy defect leads to a red-shift in both the pi and sigma spectra. A pyridinic nitrogen at the 6V defect center exhibits a sharp pi* peak at 398.4 eV, which agrees well with the experimental pre-edge structure at 398.6 eV. The sigma* peak is split in two, which can serve as the fingerprint to reveal the nature of the defect. A structural change from pyridinic to pyrrolic NG results in a distinctive difference in the spectral shape. The ground-state band structure has also been simulated at the DFT level with periodic boundary conditions. Similar profiles are found in the N 2p projected density of states above the Fermi level and in the N 1s NEXAFS spectra.
Place, publisher, year, edition, pages
2015. Vol. 119, no 29, 16660-16666 p.
IdentifiersURN: urn:nbn:se:kth:diva-172714DOI: 10.1021/acs.jpcc.5b03981ISI: 000358624000029ScopusID: 2-s2.0-84937900185OAI: oai:DiVA.org:kth-172714DiVA: diva2:849978
QC 201508312015-08-312015-08-272016-04-29Bibliographically approved