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Naji, M. |
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Motta, Antonella |
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Aletan, Dirar |
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Mohamed, Tarek |
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Ertürk, Emre |
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Taccardi, Nicola |
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Kononenko, Denys |
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Petrov, R. H. | Madrid |
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Alshaaer, Mazen | Brussels |
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Bih, L. |
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Casati, R. |
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Muller, Hermance |
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Kočí, Jan | Prague |
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Šuljagić, Marija |
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Kalteremidou, Kalliopi-Artemi | Brussels |
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Azam, Siraj |
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Ospanova, Alyiya |
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Blanpain, Bart |
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Ali, M. A. |
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Popa, V. |
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Rančić, M. |
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Ollier, Nadège |
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Azevedo, Nuno Monteiro |
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Landes, Michael |
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Rignanese, Gian-Marco |
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Meskers, Stefan C. J.
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (29/29 displayed)
- 2023Origin and Energy of Intra-Gap States in Sensitive Near-Infrared Organic Photodiodescitations
- 2023Origin and Energy of Intra-Gap States in Sensitive Near-Infrared Organic Photodiodescitations
- 2021Photo-controlled alignment and helical organization in main-chain liquid crystalline alternating polymerscitations
- 2021Consequences of Chirality in Directing the Pathway of Cholesteric Helix Inversion of π-Conjugated Polymers by Lightcitations
- 2021Consequences of Chirality in Directing the Pathway of Cholesteric Helix Inversion of π-Conjugated Polymers by Lightcitations
- 2021Ultralow dark current in near-infrared perovskite photodiodes by reducing charge injection and interfacial charge generationcitations
- 2020Long-lived charge-transfer state from B−N frustrated Lewis pairs enchained in supramolecular copolymerscitations
- 2020Long-lived charge-transfer state from B−N frustrated Lewis pairs enchained in supramolecular copolymerscitations
- 2020Circularly Polarized Photoluminescence from Chiral Perovskite Thin Films at Room Temperaturecitations
- 2020On the origin of dark current in organic photodiodescitations
- 2019Impact of polymorphism on the optoelectronic properties of a low-bandgap semiconducting polymercitations
- 2018The effect of oxygen on the efficiency of planar p-i-n metal halide perovskite solar cells with a PEDOT:PSS hole transport layercitations
- 2018Bis(arylimidazole) iridium picolinate emitters and preferential dipole orientation in filmscitations
- 2017Thiophene rings improve the device performance of conjugated polymers in polymer solar cells with thick active layerscitations
- 2017Ultrafast charge and triplet state formation in Diketopyrrolopyrrole Low Band Gap Polymer/Fullerene blendscitations
- 2014Photoluminescence quenching in films of conjugated polymers by electrochemical dopingcitations
- 2014Effect of the fibrillar microstructure on the efficiency of high molecular weight diketopyrrolopyrrole-based polymer solar cellscitations
- 2014Relation between the electroforming voltage in alkali halide-polymer diodes and the bandgap of the alkali halidecitations
- 2012Electroforming process in metal-oxide-polymer resistive switching memories
- 2012Role of hole injection in electroforming of LiF-polymer memory diodescitations
- 2010Trapping of electrons in metal oxide-polymer memory diodes in the initial stage of electroformingcitations
- 2008Compositional and electric field dependence of the dissociation of charge transfer excitons in alternating polyfluorene copolymer/fullerene blendscitations
- 2006Synthesis and characterization of long perylenediimide polymer fibers : from bulk to the single-molecule levelcitations
- 2006Electronic memory effects in a sexithiophene - poly(ethylene oxide) block copolymer doped with NaCl. combined diode and resistive switching behaviorcitations
- 2006Triplet formation from the charge-separated state in blends of MDMO-PPV with cyano-containing acceptor polymerscitations
- 2005Exciplex dynamics in a conjugated polymer blend of MDMO-PPV and PCNEPV
- 2003Thermally induced transient absorption of light by poly(3,4-ethylenedioxythiophene):Poly(styrene sulfonic acid) (PEDOT:PSS) films: A way to probe charge-carrier thermalization processescitations
- 2002Simulation of electrical conductivity in a pi-conjugated polymeric conductor with infrared lightcitations
- 2000Relaxation of photo-excitations in films of oligo- and poly-(para-phenylene vinylene) derivativescitations
Places of action
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article
Compositional and electric field dependence of the dissociation of charge transfer excitons in alternating polyfluorene copolymer/fullerene blends
Abstract
The electro-optical properties of thin films of electron donor-acceptor blends of a fluorene copolymer (PF10TBT) and a fullerene derivative (PCBM) were studied. Transmission electron microscopy shows that in these films nanocrystalline PCBM clusters are formed at high PCBM content. For all concentrations, a charge transfer (CT) transition is observed with absorption spectroscopy, photoluminescence, and electroluminescence. The CT emission is used as a probe to investigate the dissociation of CT excited states at the donor-acceptor interface in photovoltaic devices, as a function of an applied external electric field and PCBM concentration. We find that the maximum of the CT emission shifts to lower energy and decreases in intensity with higher PCBM content. We explain the red shift of the emission and the lowering of the open-circuit voltage (VOC) of photovoltaic devices prepared from these blends with the higher relative permittivity of PCBM (?r = 4.0) compared to that of the polymer (?r = 3.4), stabilizing the energy (ECT) of CT states and of the free charge carriers in blends with higher PCBM concentration. We show that the CT state has a short decay time (? = ca. 4 ns) that is reduced by the application of an external electric field or with increasing PCBM content. The field-induced quenching can be explained quantitatively with the Onsager-Braun model for the dissociation of the CT states when including a high electron mobility in nanocrystalline PCBM clusters. Furthermore, photoinduced absorption spectroscopy shows that increasing the PCBM concentration reduces the yield of neutral triplet excitons forming via electron-hole recombination, and increases the lifetime of radical cations. The presence of nanocrystalline domains with high local carrier mobility of at least one of the two components in an organic heterojunction may explain efficient dissociation of CT states into free charge carriers. © 2008 American Chemical Society