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Bernius, Mark T.; Inbasekaran, M.; Woo, E. P.; Wu, Wenbing; Wujkowski, Lisa

doi:10.1023/a:1008917128880

Cited by 125 publications

(111 citation statements)

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“…These are very similar to that for TFB, [ 36 ] and other fl uorene-triarylamine copolymers are also found to only exhibit this second-order glass transition. [ 38,45 ] This is very different from that of polycrystalline polymers such as P3HT, poly(9,9-dioctylfl uorene) (PFO), poly(9,9-dioctylfl uorene-alt -benzothiadiazole) (F8BT), and poly(9,9-dioctylfl uorene-alt -bithiophene), which can have rich and complex DSC spectra showing multiple peaks from glass, crystallization, and melting transitions. [ 36,[46][47][48][49][50][51] The thin fi lm optical absorption spectra of PFB and PFMO (Figure 2 resemble the solution spectra using a good solvent in which the chains are in the random-coil conformation.…”

Section: Resultsmentioning

confidence: 95%

Charge‐Carrier Density Independent Mobility in Amorphous Fluorene‐Triarylamine Copolymers

Campbell

Rawcliffe

Guite

et al. 2016

Adv Funct Materials

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3720 wileyonlinelibrary.com (OPVs), and organic fi eld-effect transistors (OFETs). A crucial parameter in the development of these technologies is the OSC charge-carrier mobility, and how it is related to the different OSC materials, processing, device architectures, and device operating conditions. Many semiconducting polymers and small molecules are amorphous, and such disorder in the physical morphology is expected to refl ect itself in disorder of the energy levels of the hole and electron transport states ( Figure 1 a). Such energetic disorder will directly impact charge transport and mobility. [1][2][3][4][5][6][7][8][9][10][11][12] For such energetically disordered OSCs, one feature predicted by many charge transport models is a charge-carrier density dependent mobility. The original Gaussian disorder model (GDM) developed by Bässler for hopping transport in a Gaussian density of states (DOS) distribution was a single carrier approach, [ 1 ] as were the models based on it which considered both correlated energetic disorder, [ 2 ] with a smoothly varying energy landscape (see Figure 1 a), and the effect of polaronic relaxation. [ 3 ] The percolation model developed by Vissenberg and Matters for transport involving an exponential DOS instead considered multiple carriers, [ 4 ] and this predicted a mobility which has a power-law dependency on the charge-carrier density. The measured transistor mobility falls two to three orders of magnitude below that predicted from the charge-carrier density dependent model, and does not follow the expected power-law relationship. The experimental results for these two amorphous polymers are therefore consistent with a charge-carrier density independent mobility, and this is discussed in terms of polaron-dominated hopping and interchain correlated disorder.

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Section: Resultsmentioning

confidence: 95%

Charge‐Carrier Density Independent Mobility in Amorphous Fluorene‐Triarylamine Copolymers

Campbell

Rawcliffe

Guite

et al. 2016

Adv Funct Materials

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“…A c c e p t e d m a n u s c r i p t 4 Here, we report on the luminescence properties of PFO/PVK blends and show that the use of the hole-transporting polymer PVK is successful at suppressing the green emission. The molecular structures of these polymers are shown in scheme 1.…”

Section: Introductionmentioning

confidence: 86%

“…Polyfluorenes, PFs, are among the most studied EL conjugated polymers [4], the homopolymers being blue emitters. Emission colour can be tuned by copolymerisation with lower energy gap comonomers [5] or through blending with low energy gap polymers [6,7].…”

Section: Introductionmentioning

confidence: 99%

Luminescence properties of poly(9,9-dioctylfluorene)/polyvinylcarbazole blends: Role of composition on the emission colour stability and electroluminescence efficiency

Bernardo

Charas

Morgado

2010

Journal of Physics and Chemistry of Solids

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Light-emitting diodes (LEDs), based on blue-emitting polyfluorenes are usually prone to the appearance of a contaminant green emission (centered around 520 nm), leading to an apparent whitish light emission. We find that, for LEDs based on poly(9,9-dioctylfluorene), PFO, the blending with the hole transporting polyvinylcarbazole, PVK, can suppress such green emission. LEDs based on a PFO/PVK blend with a 1:2 weight ratio and with aluminum cathodes show a quite stable blue emission. This result reveals the important role played by the interchain interactions on the observed contaminant green emission. In addition, we observe that in Al-based devices blending A c c e p t e d m a n u s c r i p t 2 causes a decrease in EL efficiency while in Mg-based devices we obtained higher efficiencies with the blend PFO:3PVK when comparing with neat PFO-based devices.

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“…QY measurements show the highest value for F 1 monomer, characterised by a rigid highly planar structure; consistently, systems like fluorene are widely used as emitters for OLED applications [66,67]. Excited state C 1 structure is very similar to F 1 (Figure 3), but the QY is about the half, probably due to the presence of heteroatom; C' 1 shows a QY about one tenth of C 1 one because the LUMO state is not completely rigid, and the thienyl units are free to rotate, thus increasing the non-radiative decay constant (k nr ) (vide supra).…”

Section: Uv-vis Spectroscopymentioning

confidence: 94%

Ternary thiophene–X–thiophene semiconductor building blocks (X=fluorene, carbazole, phenothiazine): Modulating electronic properties and electropolymerization ability by tuning the X core

Tacca

Pò

Caldararo

et al. 2011

Electrochimica Acta

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To achieve rationalization criteria for target-oriented molecular design of Th-X-Th (Th = thiophene) semiconductor building blocks, we have carried out an extensive investigation on the effects of the X core (X = fluorene, carbazole or phenothiazine) on the electronic properties and polymerization ability of Th-X-Th monomers and on the electronic and structural properties of the corresponding periodic conducting polymers -(Th-X-Th) n -, obtained by electropolymerization and, for

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Cited by 125 publications

References 0 publications

Charge‐Carrier Density Independent Mobility in Amorphous Fluorene‐Triarylamine Copolymers

Charge‐Carrier Density Independent Mobility in Amorphous Fluorene‐Triarylamine Copolymers

Luminescence properties of poly(9,9-dioctylfluorene)/polyvinylcarbazole blends: Role of composition on the emission colour stability and electroluminescence efficiency

Ternary thiophene–X–thiophene semiconductor building blocks (X=fluorene, carbazole, phenothiazine): Modulating electronic properties and electropolymerization ability by tuning the X core

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