Publication detail
Raman antenna effect from exciton–phonon coupling in organic semiconducting nanobelts
WANG, M. GONG, Y. ALZINA, F. SVOBODA, O. BALLESTEROS, B. TORRES, C. XIAO, S. HE, J. ZHANG, Z.
English title
Raman antenna effect from exciton–phonon coupling in organic semiconducting nanobelts
Type
journal article in Web of Science
Language
en
Original abstract
The highly anisotropic interactions in organic semiconductors together with the soft character of organic materials lead to strong coupling between nuclear vibrations and exciton dynamics, which potentially results in anomalous electrical, optical and optoelectrical properties. Here, we report on the Raman antenna effect from organic semiconducting nanobelts 6,13-dichloropentacene (DCP), resulting from the coupling of molecular excitons and intramolecular phonons. The highly ordered crystalline structure in DCP nanobelts enables the precise polarization-resolved spectroscopic measurement. The angle-dependent Raman spectroscopy under resonant excitation shows that all Raman modes from the skeletal vibrations of DCP molecule act like a nearly perfect dipole antenna IRaman ∝ cos4(θ − 90), with almost zero (maximum) Raman scattering parallel (perpendicular) to the nanobelt's long-axis. The Raman antenna effect in DCP nanobelt is originated from the coupling between molecular skeletal vibrations and intramolecular exciton and the confinement of intermolecular excitons. It dramatically enhances the Raman polarization ratio (ρ = I‖/I⊥ > 25) and amplifies the anisotropy of the angle-dependent Raman scattering (κRaman = Imax/Imin > 12) of DCP nanobelts. These findings have crucial implications for fundamental understanding on the exciton–phonon coupling and its effects on the optical properties of organic semiconductors.
English abstract
The highly anisotropic interactions in organic semiconductors together with the soft character of organic materials lead to strong coupling between nuclear vibrations and exciton dynamics, which potentially results in anomalous electrical, optical and optoelectrical properties. Here, we report on the Raman antenna effect from organic semiconducting nanobelts 6,13-dichloropentacene (DCP), resulting from the coupling of molecular excitons and intramolecular phonons. The highly ordered crystalline structure in DCP nanobelts enables the precise polarization-resolved spectroscopic measurement. The angle-dependent Raman spectroscopy under resonant excitation shows that all Raman modes from the skeletal vibrations of DCP molecule act like a nearly perfect dipole antenna IRaman ∝ cos4(θ − 90), with almost zero (maximum) Raman scattering parallel (perpendicular) to the nanobelt's long-axis. The Raman antenna effect in DCP nanobelt is originated from the coupling between molecular skeletal vibrations and intramolecular exciton and the confinement of intermolecular excitons. It dramatically enhances the Raman polarization ratio (ρ = I‖/I⊥ > 25) and amplifies the anisotropy of the angle-dependent Raman scattering (κRaman = Imax/Imin > 12) of DCP nanobelts. These findings have crucial implications for fundamental understanding on the exciton–phonon coupling and its effects on the optical properties of organic semiconductors.
Keywords in English
FIELD-EFFECT TRANSISTORS; CHARGE-TRANSPORT; SINGLE-CRYSTALS; SPECTROSCOPY; PENTACENE; 6,13-DICHLOROPENTACENE; FABRICATION; NANOWIRES; POLYMER; DEVICES
Released
27.11.2017
Publisher
ROYAL SOC CHEMISTRY
Location
THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND
ISSN
2040-3364
Volume
9
Number
48
Pages from–to
19328–19336
Pages count
9
BIBTEX
@article{BUT143260,
author="Mao {Wang} and Yi {Gong} and Francesc {Alzina} and Ondřej {Svoboda} and Belén {Ballesteros} and Clivia Marfa Sotomayor {Torres} and Senbo {Xiao} and Jianying {He} and Zhiliang {Zhang},
title="Raman antenna effect from exciton–phonon coupling in organic semiconducting nanobelts",
year="2017",
volume="9",
number="48",
month="November",
pages="19328--19336",
publisher="ROYAL SOC CHEMISTRY",
address="THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND",
issn="2040-3364"
}