Semiconductor-to-Metal Transition in Carbon-Atom Wires
Driven by sp<sup>2</sup> Conjugated End Groups
Alberto Milani
Matteo Tommasini
Valentino Barbieri
Andrea Lucotti
Valeria Russo
Franco Cataldo
Carlo S. Casari
10.1021/acs.jpcc.7b02246.s001
https://acs.figshare.com/articles/journal_contribution/Semiconductor-to-Metal_Transition_in_Carbon-Atom_Wires_Driven_by_sp_sup_2_sup_Conjugated_End_Groups/4982942
Bis(biphenyl)-capped
polyynes are investigated to unveil the modulation
of the electronic and optical properties of sp-hybridized carbon-atom
wires (CAWs) capped with π-conjugated sp<sup>2</sup> end groups.
Raman and surface enhanced Raman spectroscopy experiments and density
functional theory (DFT) calculations reveal structural changes from
polyyne-like with alternating single–triple bonds toward cumulene-like
with more equalized bonds as a consequence of the charge transfer
occurring when wires interact with metallic nanoparticles. While polyynes
have semiconducting electronic properties, a more equalized system
tends to a cumulene-like structure characterized by a nearly metallic
behavior. The effect of different sp<sup>2</sup> end groups in driving
a semiconductor-to-metal transition is investigated by DFT calculations
on a series of CAWs capped with different terminations. We discuss
how the modulation of the structural, electronic, and vibrational
properties of the sp-carbon chain toward the metallic wire is not
trivial and requires a suitable chemical design of the end group and
control of charge transfer. These results provide a guideline for
the design of novel sp–sp<sup>2</sup> hybrid carbon nanosystems
with tunable properties, where graphene-like and polyyne-like domains
are closely interconnected. The capability to tune the final electronic
or optical response of the material makes these hybrid sp–sp<sup>2</sup> systems appealing for a future all-carbon-based science and
technology.
2017-04-24 00:00:00
sp-hybridized carbon-atom wires
equalized
charge transfer
cumulene-like
Raman spectroscopy experiments
sp 2 end groups
polyyne-like
polyyne
bond
future all-carbon-based science
DFT
calculation
CAW
modulation