Journal ArticleDOI
The electronic states of polyfluorene copolymers with alternating donor-acceptor units.
Kim G. Jespersen,Wichard J. D. Beenken,Yuri Zaushitsyn,Arkady Yartsev,Mats Andersson,Tõnu Pullerits,Villy Sundström +6 more
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TLDR
The semiempirical quantum-chemical (ZINDO) method can assign the characteristic bands of the "camel-back" absorption spectrum to one charge transfer state at lower energy localized on the TBT unit, and one delocalized excitonic state at higher energy corresponding to the pi-conjugated electron system.Abstract:
We calculate the electronic states of the low bandgap polyfluorene-based copolymer DiO-PFDTBT, which consists of alternating 9,9-dioctyl-9H-fluorene and 4,7-di-thiophen-2-ylbenzo[1,2,5]thiadiazole (TBT) units, and compare with the steady-state absorption, emission, and excitation spectrum. Using the semiempirical quantum-chemical (ZINDO) method we can assign the characteristic bands of the “camel-back” absorption spectrum to one charge transfer state at lower energy localized on the TBT unit, and one delocalized excitonic state at higher energy corresponding to the π-conjugated electron system. Additional “dark” charge transfer states in the gap between these bands have been revealed. Calculations are also made on the red light emitting polyfluorene-based copolymer poly(fluorene-co-benzothiadiazole) (F8BT), which contains benzo[1,2,5]thiadiazole instead of TBT. The nature of the electronic states in F8BT and DiO-PFDTBT are found to be qualitatively the same.read more
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Low band gap polymers for organic photovoltaics
Eva Bundgaard,Frederik C. Krebs +1 more
TL;DR: Low band gap polymer materials and their application in organic photovoltaics (OPV) are reviewed in this paper, where the authors provide a compilation of the most studied classes of low band gap materials.
Journal ArticleDOI
Examining the Effect of the Dipole Moment on Charge Separation in Donor–Acceptor Polymers for Organic Photovoltaic Applications
Bridget Carsten,Jodi M. Szarko,Hae Jung Son,Wei Wang,Luyao Lu,Feng He,Brian S. Rolczynski,Sylvia J. Lou,Lin X. Chen,Luping Yu +9 more
TL;DR: PBB3 showed a long-lived excitonic state and the slowest electron transfer dynamics of the series of polymers, as well as the fastest recombination rate of the charge-separated (CS) species, indicating that electrons and holes are more tightly bound in these species.
Journal ArticleDOI
Aggregation in a high-mobility n-type low-bandgap copolymer with implications on semicrystalline morphology.
Robert Steyrleuthner,Marcel Schubert,Ian A. Howard,Bastian Klaumünzer,Kristian Schilling,Zhihua Chen,Peter Saalfrank,Frédéric Laquai,Antonio Facchetti,Dieter Neher +9 more
TL;DR: It is concluded that film formation is mainly governed by the chain collapse, leading in general to a high aggregate content of ~45% and inhibits the formation of amorphous and disordered P(NDI2OD-T2) films.
Journal ArticleDOI
Influence of Aggregation on the Performance of All-Polymer Solar Cells Containing Low-Bandgap Naphthalenediimide Copolymers
Marcel Schubert,Daniel Dolfen,Johannes Frisch,Steffen Roland,Robert Steyrleuthner,Burkhard Stiller,Zhihua Chen,Ullrich Scherf,Norbert Koch,Antonio Facchetti,Dieter Neher +10 more
TL;DR: In this paper, the authors present efficient all-polymer solar cells comprising two different low-bandgap naphthalenediimide (NDI)-based copolymers as acceptors and regioregular P3HT as the donor.
Journal ArticleDOI
Photoconductivity of a Low-Bandgap Conjugated Polymer†
Cesare Soci,In-Wook Hwang,Daniel Moses,Zhengguo Zhu,David Waller,Russel Gaudiana,Christoph J. Brabec,Alan J. Heeger +7 more
TL;DR: In this article, the photoconductive properties of a low-bandgap conjugated polymer, poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta]dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)], PCPDTBT, with an optical energy gap of Eg'∼'1.5'eV, have been studied.
References
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TL;DR: In this paper, the interpenetrating network formed from a phase-segregated mixture of two semiconducting polymers is shown to provide both the spatially distributed interfaces necessary for efficient charge photo-generation, and the means for separately collecting the electrons and holes.
Journal ArticleDOI
2.5% efficient organic plastic solar cells
Sean E. Shaheen,Christoph J. Brabec,N. Serdar Sariciftci,F. Padinger,Thomas Fromherz,Jan C. Hummelen +5 more
TL;DR: In this article, the power conversion efficiency of organic photovoltaic devices based on a conjugated polymer/methanofullerene blend is dramatically affected by molecular morphology.
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Optical properties of disordered molecular aggregates: a numerical study
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Journal ArticleDOI
Design of Narrow-Bandgap Polymers. Syntheses and Properties of Monomers and Polymers Containing Aromatic-Donor and o-Quinoid-Acceptor Units
TL;DR: A series of novel monomers and polymers containing aromatic-donor and o-quinoid-acceptor units was prepared, and the relationship between their spectral and electrochemical properties and their structures was investigated as discussed by the authors.