The effect of ketone defects on the charge transport and charge recombination in polyfluorenes
| Autor: | Kuik, M., Wetzelaer, G.-J.A.H., Laddé, J.G., Nicolai, H.T., Wildeman, J., Sweelssen, J., Blom, P.W.M. |
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| Jazyk: | angličtina |
| Rok vydání: | 2011 |
| Předmět: |
Cyclic voltammetry
HOL - Holst MIP - Materials for Integrated Products Conjugated polymers Fluorenone defect Electron transport properties Polyfluorenes Organic compounds Trap depth Materials Hole transports TS - Technical Sciences Industrial Innovation Electron transport Mechatronics Mechanics & Materials organic light-emitting diodes Charge recombinations Ketones Molybdenum oxide Electron transitions Light emitting diodes characterization tools Space charges organic electronics Poly(9 9-dioctylfluorene) Trapping sites Fluorenones Trap levels Defects Polyfluorene derivative Exponential trap distribution Green emissions Ideality factors |
| Zdroj: | Advanced Functional Materials, 23, 21, 4502-4509 |
| Popis: | 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 occurrence of an exponential trap distribution with a trap depth of 0.18 eV. The electron transport in PFO is also observed to be trap limited, but in order to describe the electron transport of PFO-F, an additional trap level with a depth of 0.46 eV must be introduced. The obtained energy levels of the fluorenone trapping sites are in close agreement with cyclic voltammetry (CV) measurements reported in literature. As a result, the fluorenone defects are shown to simultaneously act as hole- and electron trap. Moreover, through ideality factor measurements, the green emission associated with these defects is observed to originate from trap-assisted recombination. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. |
| Databáze: | OpenAIRE |
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