Electronic structure of polyacetylene: Optical and infrared studies of undoped semiconducting<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mo>(</mml:mo><mml:mi mathvariant="normal">CH</mml:mi><mml:mo>)</mml:mo></mml:mrow><mml:mrow><mml:mi>x</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>and heavily doped metallic<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mo>(</mml:mo><mml:mi

Fincher, C. R.; Ozaki, Masa‐aki; Tanaka, Masashi; Peebles, D.; Lauchlan, L.; Heeger, Alan J.; MacDiarmid, Alan G.

doi:10.1103/physrevb.20.1589

Cited by 308 publications

(41 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…We tentatively assign this feature to a polaritonic stopband (59,60): a strong, characteristic reflection found between the transversal and the longitudinal exciton-polariton branches. Similar features are observed in quasione-dimensional polymer crystals and TCNQ crystals (61)(62)(63)(64). They can be rationalized with the anticrossing rule for photons and an exciton resonance in the limit of strong coupling (65).…”

Section: Resultssupporting

confidence: 54%

Low-lying excited states in crystalline perylene

Rangel

Rinn

Sharifzadeh

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Organic materials are promising candidates for advanced optoelectronics and are used in light-emitting diodes and photovoltaics. However, the underlying mechanisms allowing the formation of excited states responsible for device functionality, such as exciton generation and charge separation, are insufficiently understood. This is partly due to the wide range of existing crystalline polymorphs depending on sample preparation conditions. Here, we determine the linear optical response of thin-film single-crystal perylene samples of distinct polymorphs in transmission and reflection geometries. The sample quality allows for unprecedented high-resolution spectroscopy, which offers an ideal opportunity for judicious comparison between theory and experiment. Excellent agreement with firstprinciples calculations for the absorption based on the GW plus Bethe-Salpeter equation (GW-BSE) approach of many-body perturbation theory (MBPT) is obtained, from which a clear picture of the low-lying excitations in perylene emerges, including evidence of an exciton-polariton stopband, as well as an assessment of the commonly used Tamm-Dancoff approximation to the GW-BSE approach. Our findings on this well-controlled system can guide understanding and development of advanced molecular solids and functionalization for applications. molecular crystals | many-body perturbation theory | excited states | spectroscopy

show abstract

Section: Resultssupporting

confidence: 54%

Low-lying excited states in crystalline perylene

Rangel

Rinn

Sharifzadeh

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…2 There is no shift of the π-π*-transition during doping. 3 Effects of donor doping with Na are indistinguishable form those of acceptor doping. 4 Heterocyclic conjugated organic polymers such as polythiophene (PT) and polypyrrole (PP) (Scheme 1) behave somewhat different.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Investigation of Excited States of Large Polyene Cations as Model Systems for Lightly Doped Polyacetylene

Salzner

2006

J. Chem. Theory Comput.

View full text Add to dashboard Cite

Electronic excitations of polyene cations with chain lengths of up to 101 CH units were investigated as model systems for lightly doped polyacetylene (PA). Since high level ab initio calculations such as complete active space perturbation theory (CASPT2) are limited to systems with about 14 CH units, the performances of time-dependent Hartree-Fock (TDHF) and time-dependent density functional theory (TDDFT) were evaluated. It turned out that TDDFT excitations energies are much more accurate for polyene cations than for neutral polyenes. The difference between TDHF and TDDFT excitation energies for the first allowed excited state of C 49 H 51 + is only 0.30 eV with pure DFT and 0.21 eV with a hybrid functional. For open-shell systems, pure DFT is found to be superior to DFT-hybrid functionals because it does not suffer from spin-contamination. Pure TDDFT excitation energies and oscillator strengths for small openshell polyene cations compare well with high level ab initio results. Excitation energies are found to be almost independent of the geometry, i.e., the size of the defect. Localization of the defect, however, shifts oscillator strengths from the HOMO-LUMO transition to higher lying excited states of the same symmetry. Lightly doped PA is predicted to exhibit several strong absorptions below 1 eV.

show abstract

“…The bulk properties of the metallic polymer can be related to T, (w) and E, (q;) through effect ive-medi,.u theory (see ref. 29). The average medium conductivity can Le wrxitten afa (U) ( 14 …”

Section: I'mentioning

confidence: 99%