title: Photoluminescence of carbon nanodots: dipole emission centers and electron-phonon coupling.
abstract: Inorganic carbon nanomaterials, also called carbon nanodots, exhibit a strong photoluminescence with unusual properties and, thus, have been the focus of intense research. Nonetheless, the origin of their photoluminescence is still unclear and the subject of scientific debates. Here, we present a single particle comprehensive study of carbon nanodot photoluminescence, which combines emission and lifetime spectroscopy, defocused emission dipole imaging, azimuthally polarized excitation dipole scanning, nanocavity-based quantum yield measurements, high resolution transmission electron microscopy, and atomic force microscopy. We find that photoluminescent carbon nanodots behave as electric dipoles, both in absorption and emission, and that their emission originates from the recombination of photogenerated charges on defect centers involving a strong coupling between the electronic transition and collective vibrations of the lattice structure.
authors.affiliation: III. Institute of Physics, Georg August University , 37077 Göttingen, Germany.
authors.forename: Siddharth
authors.initials: S
authors.lastname: Ghosh
authors.forename: Anna M
authors.initials: AM
authors.lastname: Chizhik
authors.forename: Narain
authors.initials: N
authors.lastname: Karedla
authors.forename: Mariia O
authors.initials: MO
authors.lastname: Dekaliuk
authors.forename: Ingo
authors.initials: I
authors.lastname: Gregor
authors.forename: Henning
authors.initials: H
authors.lastname: Schuhmann
authors.forename: Michael
authors.initials: M
authors.lastname: Seibt
authors.forename: Kai
authors.initials: K
authors.lastname: Bodensiek
authors.forename: Iwan A T
authors.initials: IA
authors.lastname: Schaap
authors.forename: Olaf
authors.initials: O
authors.lastname: Schulz
authors.forename: Alexander P
authors.initials: AP
authors.lastname: Demchenko
authors.forename: Jörg
authors.initials: J
authors.lastname: Enderlein
authors.forename: Alexey I
authors.initials: AI
authors.lastname: Chizhik
keywords: carbon nanodots; electron−phonon coupling; fluorescence; nanoparticles; nanotechnology; transition dipole moment