Searched for: author%3A%22Nicolai%2C+H.T.%22
(1 - 17 of 17)
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Abbaszadeh, D. (author), Nicolai, H.T. (author), Crəciun, N.I. (author), Blom, P.W.M. (author)
The operation of blue light-emitting diodes based on polyspirobifluorene with a varying number of N,N,N′,N′ tetraaryldiamino biphenyl (TAD) hole-transport units (HTUs) is investigated. Assuming that the electron transport is not affected by the incorporation of TAD units, model calculations predict that a concentration of 5% HTU leads to an...
article 2014
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Abbaszadeh, D. (author), Wetzelaer, G.A.H. (author), Nicolai, H.T. (author), Blom, P.W.M. (author)
The quenching of excitons at the poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid) PEDOT:PSS) anode in blue polyalkoxyspirobifluorene-arylamine polymer light-emitting diodes is investigated. Due to the combination of a higher electron mobility and the presence of electron traps, the recombination zone shifts from the cathode to the...
article 2014
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Nicolai, H.T. (author), Hof, A. (author), Blom, P.W.M. (author)
The charge transport and recombination in white-emitting polymer light- emitting diodes (PLEDs) are studied. The PLED investigated has a single emissive layer consisting of a copolymer in which a green and red dye are incorporated in a blue backbone. From single-carrier devices the effect of the green- and red-emitting dyes on the hole and...
article 2012
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Nicolai, H.T. (author), Hof, A.J. (author), Lu, M. (author), Blom, P.W.M. (author), de Vries, R.J. (author), Coehoorn, R. (author)
article 2012
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Lu, M. (author), de Bruyn, P. (author), Nicolai, H.T. (author), Wetzelaer, G.-J.A.H. (author), Blom, P.W.M. (author)
article 2012
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Nicolai, H.T. (author), Kuik, M. (author), Wetzelaer, G.A.H. (author), de Boer, B. (author), Campbell, C. (author), Risko, C. (author), Brédas, J.L. (author), Blom, P.W.M. (author)
Electron transport in semiconducting polymers is usually inferior to hole transport, which is ascribed to charge trapping on isolated defect sites situated within the energy bandgap. However, a general understanding of the origin of these omnipresent charge traps, as well as their energetic position, distribution and concentration, is lacking....
article 2012
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Nicolai, H.T. (author), Hof, A. (author), Oosthoek, J.L.M. (author), Blom, P.W.M. (author)
The charge transport in blue light-emitting polyspirobifluorene is investigated by both steady-state current-voltage measurements and transient electroluminescence. Both measurement techniques yield consistent results and show that the hole transport is space-charge limited. The electron current is found to be governed by a high intrinsic...
article 2011
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Lu, M. (author), Nicolai, H.T. (author), Wetzelaer, G.-J.A.H. (author), Blom, P.W.M. (author)
The electron transport in poly(p-phenylene vinylene) (PPV) derivatives blended with the air-stable n-type dopant (4-(1,3-dimethyl-2,3-dihydro-1H- benzoimidazol-2-yl)phenyl)dimethylamine (N-DMBI) is investigated. This dopant is activated after thin film deposition by annealing and strongly enhances the electron transport due to filling of...
article 2011
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Jarzab, D. (author), Lu, M. (author), Nicolai, H.T. (author), Blom, P.W.M. (author), Loi, M.A. (author)
Here we report on a combined photoluminescence and morphological study of a polymer-polymer blend composed of a copolymer of derivatives of polyspirobifluorene and polyfluorene (PBFF) and a derivative of polyphenylene vinylene (MDMO-PPV). Evidence of partial Förster energy transfer from PBFF to MDMO-PPV is revealed by steady-state and time...
article 2011
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Kuik, M. (author), Nicolai, H.T. (author), Lenes, M. (author), Wetzelaer, G.-J.A.H. (author), Lu, M. (author), Blom, P.W.M. (author)
The recombination processes in poly(p -phenylene vinylene) based polymer light-emitting diodes (PLEDs) are investigated. Photogenerated current measurements on PLED device structures reveal that next to the known Langevin recombination also trap-assisted recombination is an important recombination channel in PLEDs, which has not been considered...
article 2011
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Kuik, M. (author), Wetzelaer, G.-J.A.H. (author), Laddé, J.G. (author), Nicolai, H.T. (author), Wildeman, J. (author), Sweelssen, J. (author), Blom, P.W.M. (author)
The effect of on-chain ketone defects on the charge transport of the polyfluorene derivative poly(9,9-dioctylfluorene) (PFO) is investigated. Using MoO3 as ohmic hole contact, the hole transport in a pristine PFO diode is observed to be limited by space-charge, whereas fluorenone contaminated PFO (PFO-F) is shown to be trap limited by the...
article 2011
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Nicolai, H.T. (author), Hof, A.J. (author), Lu, M. (author), Blom, P.W.M. (author), de Vries, R.J. (author), Coehoorn, R. (author)
The charge transport in a polyspirobifluorene derivative with copolymerized N,N,N',N'-tetraaryldiamino biphenyl (TAD) hole transport units is investigated as a function of the TAD content. For TAD concentrations larger than 5, guest-to-guest transport is observed. It is demonstrated that in this regime the charge carrier density dependent...
article 2011
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Lu, M. (author), Nicolai, H.T. (author), Wetzelaer, G.-J.A.H. (author), Blom, P.W.M. (author)
N-type doping of poly(2-methoxy-5-(2′-ethyl-hexyloxy)-p-phenylene vinylene) (MEH-PPV) with decamethylcobaltocene (DMC) strongly improves the electron transport due to filling of the electron traps. Unexpectedly, the n-type doping simultaneously suppresses the hole transport in MEH-PPV. We demonstrate that this strong reduction of the hole...
article 2011
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Lu, M. (author), Nicolai, H.T. (author), Kuik, M. (author), Wetzelaer, G.-J.A.H. (author), Wildeman, J. (author), Palmaerts, A. (author), Blom, P.W.M. (author)
We demonstrate a solution processed bi-layer PLED based on poly(p-phenylene vinylene) derivatives using orthogonal solvents. To lower the voltage drop the hole transport layer (HTL) based on poly[2,5-bis(2-ethylhexyloxy)-co-2,5- bis(butoxy)-1,4-phenylenevinylene] (BEH/BB-PPV (1:3)) is doped with tetracyano-tetrafluoro-quinodimethane (F4TCNQ)....
article 2011
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Wetzelaer, G.A.H. (author), Kuik, M. (author), Nicolai, H.T. (author), Blom, P.W.M. (author)
Trapping of charges is known to play an important role in the charge transport of organic semiconductors, but the role of traps in the recombination process has not been addressed. Here we show that the ideality factor of the current of organic light-emitting diodes (OLEDs) in the diffusion-dominated regime has a temperature-independent value of...
article 2011
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Nicolai, H.T. (author), Mandoc, M.M. (author), Blom, P.W.M. (author)
The low electron currents in poly(dialkoxy-p-phenylene vinylene) (PPV) derivatives and their steep voltage dependence are generally explained by trap-limited conduction in the presence of an exponential trap distribution. Here we demonstrate that the electron transport of several PPV derivatives can also be well described with a trap...
article 2011
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Craciun, N.I. (author), Zhang, Y. (author), Palmaerts, A. (author), Nicolai, H.T. (author), Kuik, M. (author), Kist, R.J.P. (author), Wetzelaer, G.A.H. (author), Wildeman, J. (author), Vandenbergh, J. (author), Lutsen, L. (author), Vanderzande, D. (author), Blom, P.W.M. (author), TNO Industrie en Techniek (author)
The interpretation of electron currents in conjugated polymers is strongly hindered by the occurrence of hysteresis. We investigate the transport of electrons in electron-only devices based on derivatives of poly(p-phenylene vinylene) (PPV) for various hole-blocking bottom electrodes as well as purification of the polymer. The use of a variety...
article 2010
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