title: Coherent anti-Stokes Raman scattering enhancement of thymine adsorbed on graphene oxide.
abstract: Coherent anti-Stokes Raman scattering (CARS) of carbon nanostructures, namely, highly oriented pyrolytic graphite, graphene nanoplatelets, graphene oxide, and multiwall carbon nanotubes as well CARS spectra of thymine (Thy) molecules adsorbed on graphene oxide were studied. The spectra of the samples were compared with spontaneous Raman scattering (RS) spectra. The CARS spectra of Thy adsorbed on graphene oxide are characterized by shifts of the main bands in comparison with RS. The CARS spectra of the initial nanocarbons are definitely different: for all investigated materials, there is a redistribution of D- and G-mode intensities, significant shift of their frequencies (more than 20 cm(-1)), and appearance of new modes about 1,400 and 1,500 cm(-1). The D band in CARS spectra is less changed than the G band; there is an absence of 2D-mode at 2,600 cm(-1) for graphene and appearance of intensive modes of the second order between 2,400 and 3,000 cm(-1). Multiphonon processes in graphene under many photon excitations seem to be responsible for the features of the CARS spectra. We found an enhancement of the CARS signal from thymine adsorbed on graphene oxide with maximum enhancement factor about 10(5). The probable mechanism of CARS enhancement is discussed.
authors.affiliation: Institute of Physics, National Academy of Sciences of Ukraine, 46 Nauki Ave, Kyiv 03680, Ukraine.
authors.forename: Galyna
authors.initials: G
authors.lastname: Dovbeshko
authors.affiliation: Institute of Physics, National Academy of Sciences of Ukraine, 46 Nauki Ave, Kyiv 03680, Ukraine.
authors.forename: Olena
authors.initials: O
authors.lastname: Fesenko
authors.affiliation: Institute of Physics, Center for Physical Sciences and Technology, A. Goštauto 11, Vilnius LT-01108, Lithuania.
authors.forename: Andrej
authors.initials: A
authors.lastname: Dementjev
authors.affiliation: Institute of Physics, Center for Physical Sciences and Technology, A. Goštauto 11, Vilnius LT-01108, Lithuania.
authors.forename: Renata
authors.initials: R
authors.lastname: Karpicz
authors.affiliation: Nikolaev Institute of Inorganic Chemistry, Siberian Branch of RAS, Akad. Lavrentiev Ave. 3, Novosibirsk 630090, Russia.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Fedorov
authors.affiliation: L.V. Pisarzhevsky Institute of Physical Chemistry, National Academy of Sciences of Ukraine, 31 Nauki Ave, 03028 Kyiv, Ukraine.
authors.forename: Oleg Yu
authors.initials: OY
authors.lastname: Posudievsky
keywords: Coherent anti-Stokes Raman scattering (CARS); Graphene nanoplatelets (GNPs); Graphene oxide (GO); Graphene oxide-enhanced coherent anti-Stokes Raman scattering (GECARS); Highly oriented pyrolytic graphite (HOPG); Multiwall carbon nanotubes (MWCNTs); Surface-enhanced coherent anti-Stokes Raman scattering (SECARS); Thymine, Surface-enhanced Raman scattering (SERS)