Structural Ordering in Phenyl-Substituted Polythiophenes

Aasmundtveit, Knut E.; Samuelsen, Emil J.; Mammo, Wendimagegn; Svensson, Mattias; Andersson, Mats R.; Pettersson, Lars; Inganäs, Olle

doi:10.1021/ma9911389

Cited by 62 publications

(71 citation statements)

References 15 publications

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“…The optimized cell axis are the same for PEDOT:PSSH and the two doped structures. The repeat unit of the PEDOT chain is calculated to be 7.7-7.8 Å, and the lattice parameter which determines the distance between the chains stacked on top of each other is found to be 6.9 Å, Both these values agree with previously reported experimental results [27][28]. The separation between the PEDOT chains increases from 3.56 Å in the pure PEDOT structure, to 3.83 Å in PEDOT:PSSH, and to 3.82 Å in the two doped structures.…”

Section: Resultssupporting

confidence: 89%

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The electronic structure and reflectivity of PEDOT:PSS from density functional theory

et al. 2011

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The geometric and electronic structure of condensed phase organic conducting polymer PEDOT:PSS blends has been investigated by periodic density functional theory (DFT) calculations with a generalized-gradient approximation (GGA) functional, and a plane wave basis set. The influence of the degree of doping of the PEDOT polymer on structural and optical parameters such as the reflectivity, absorbance, conductivity, dielectric function, refractive index and the energy-loss function is studied. A flip from the benzoid to the quinoid structure is observed in the calculations when the neutral PEDOT is doped by negatively charged PSS. Also the optical properties are affected by the doping. In particular, the reflectivity was found to be very sensitive to the degree of doping, where higher doping implies higher reflectivity. The reflectivity is highly anisotropic, with the dominant contribution stemming from the direction parallel to the PEDOT polymer chain.

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Section: Resultssupporting

confidence: 89%

“…A periodic PEDOT structure was built guided by the distances given for PEDOT doped with tosylate [27] and with PF 6 [28]. The geometry optimized structure (cell axes and coordinates are optimized) of the PEDOT polymer is shown in Fig.…”

Section: Methodsmentioning

confidence: 99%

The electronic structure and reflectivity of PEDOT:PSS from density functional theory

et al. 2011

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“…The way that the molecules order in the solid phase is of great importance as for example in the case of P3HT which orders in a lamellar structure. [67][68][69][70][71][72] …”

Section: Other Factorsmentioning

confidence: 99%

Low band gap polymers for organic photovoltaics

Bundgaard

Krebs

2007

Solar Energy Materials and Solar Cells

1,308

918

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i Several research groups within the area of organic photovoltaics are focusing on low band gap polymers, a type of polymer which absorbs light with wavelengths longer than 620 nm. These systems are believed to increase the efficiency of organic photovoltaics due to a better overlap of the absorption spectrum of the polymer with the solar spectrum. In this dissertation the synthesis of 16 new low band gap copolymers based on thiophene, benzothiadiazole and benzo-bis(thiadiazole) are described. The polymers have been prepared by two strategies; one using oxidative ferric chloride polymerization and one using Stille cross coupling polymerization. The polymers were purified chemically and by Size Exclusion Chromatography (SEC). The polymers were characterized by UV-vis and Ultraviolet Photoelectron Spectroscopy (UPS), and the optical band gap and the electronic structure of the polymer were determined. The copolymers show optical band gaps from 1.65 -2.0 eV for the copolymers of thiophene and benzothiadiazole, where a decrease in the band gap was observed with an increase in the number of thiophene units in the repeating unit (n = 1 -4). A band gap down to 0.65 eV was observed for the copolymers of thiophene and benzo-bis(thiadiazole). The film forming ability of the polymers was studied by attaching different alkyl side chains on the polymer back-bone, i.e. hexyl-, 2-ethylhexyl-, dodecyl-and 3,7,11-trimethyldodecyl-groups. The 3,7,11-trimethyldodecyl-group was found to give the best film forming ability and highest absorbance, when the polymer was spin coated from solvents like THF, chloroform and 1,2-dichlorobenzene. The copolymer of thiophene and benzothiadiazole with four thiophenes in the repeating unit and 3,7,11-trimethyldodecyl-group as side chains with a band gap of 1.65 eV was applied in organic photovoltaic devices with active areas of 0.1, 3 and 10 cm 2 . The morphology of the active layer was studied, and it was found that the morphology and the photovoltaic performance of the device was affected by the choice of solvent, the spin coating conditions, the concentration of polymer, the ratio between polymer and PCBM and the annealing temperature. The highest efficiency of 1 % was achieved when the ratio between the polymer and PCBM was 1:2 and the device was annealed at 110 ºC. Lifetime and incident photon to current efficiency (IPCE) of the devices are also described. Finally, the polymer was applied in hybrid PV devices based on ZnO nano-fibers and the results of these studies are given.ii Indenfor organisk solceller fokuseres i denne tid på polymere med lavt båndgap, dvs. polymerer som absorberer lys med bølgelaengder laengere end 620 nm. Disse lavbåndgabs polymere har vist sig at kunne øge effiktiviteten af organiske solceller ved et bedre overlap mellem polymerens absorptionsspektrum og solens spektrum. I denne afhandling beskrives syntesen af 16 nye lavbåndgabs copolymere som er baseret på thiophen, benzothiadiazol og benzo-bis(thiadiazol). Der blev benyttet to syntese strategier: én med oxydativ p...

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“…For a chemically and electronically very similar polythiophene, poly͓3-͑4Ј-octylphenyl͒thiophene͔ ͑POPT͒, which also shows comparable orange and blue phases, x-ray studies proved that the blue phase of this polymer has a considerable higher degree of crystallinity than the orange phase 13 and recent x-ray studies on PEOPT suggested the same trend. 14 In their blue phase the conformation of these polymers results in a much stronger interchain interaction ͑ stacking, aggregates͒ thereby causing the shift of the HOMO-LUMO levels. A similar phenomenon was observed recently for other regioregular polythiophenes.…”

Section: B Excited-state Spectroscopymentioning

confidence: 99%

“…12 For a series of regioregular substituted poly͑3-phenylthiophenes͒ this phenomena of two different phases was studied extensively by x-ray diffraction. 13,14 In general, the class of substituted poly͑3-phenylthiophenes͒ is semi- A highly interesting phenomena is observed for many of the poly͑3-phenylthiophenes͒ with a para substitution of the phenyl ring. Depending on the processing conditions, spin-coated thin films of these polymers can exist in two distinct states with different crystallinity: a less crystalline state with a larger spacing of the highest occupiedlowest unoccupied molecular orbital ͑HOMO-LUMO͒ distance and a higher crystalline state with a lower HOMO-LUMO distance.…”

Section: Introductionmentioning

confidence: 99%

Influence of disorder on the photoinduced excitations in phenyl substituted polythiophenes

Brabec

Winder

Scharber

et al. 2001

The Journal of Chemical Physics

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Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. Regioregular poly͑3-͑4Ј-͑1Љ,4Љ,7Љ-trioxaoctyl͒phenyl͒thiophenes͒ ͑PEOPTs͒ exhibit interesting properties for the use in polymer electronics. Exposing thin films of the amorphous, disordered phase ͑orange phase͒ of the ''as prepared'' polymer to chloroform vapor or annealing them by heat treatment results in a redshift of the absorption maximum due to the formation of nanocrystals in an ordered phase ͑blue phase͒. As such, PEOPT thus is a very interesting conjugated polymeric material, which exhibits two different phases with well-defined order/disorder characters on one-and-the-same material. This property opens up the unique possibility to investigate the role of order/disorder on the photoexcited pattern without being obscured by the differences in chemical structure by using different materials with different crystallinity. The fact, that blue phase PEOPT exhibits absorption edges at relatively low energies around 1.8 eV, thereby demonstrating an enhanced spectral absorption range as compared to the orange phase, makes them attractive for use in photodiodes and solar cells as well. The photoinduced charge generation efficiency in both phases of PEOPT is significantly enhanced by the addition of a strong electron acceptor such as fullerene C 60 , as observed by quenching of the luminescence and by photoinduced absorption measurements in the infrared and uv-visible regime. The average number and the lifetime of photoinduced carriers in composites of PEOPT with a methanofullerene ͓6,6͔-phenyl C 61 -butyric acid methyl ester ͑PCBM͒ are found to depend on the crystallinity of PEOPT in thin films, which gives rise to charged photoexcitations delocalized between polymer chains. Stronger bimolecular recombination in composites of the blue phase PEOPT with PCBM is observed as compared to the orange phase PEOPT/PCBM films. The origin of this enhanced recombination is found to be related to the hole mobility of the polymer.

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Structural Ordering in Phenyl-Substituted Polythiophenes

Cited by 62 publications

References 15 publications

The electronic structure and reflectivity of PEDOT:PSS from density functional theory

The electronic structure and reflectivity of PEDOT:PSS from density functional theory

Low band gap polymers for organic photovoltaics

Influence of disorder on the photoinduced excitations in phenyl substituted polythiophenes

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