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  • 1. Bergues, B.
    et al.
    Rivas, D. E.
    Weidman, M.
    Muschet, Alexander
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik. Max-Planck-Institut für Quantenoptik, Hans-Kopfermann Strasse 1, 85748, Garching, Germany.
    Helml, W.
    Guggenmos, A.
    Pervak, V.
    Matyba, Piotr
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Kleineberg, U.
    Marcus, G.
    Kienberger, R.
    Charalambidis, D.
    Tzallas, P.
    Schröder, H.
    Krausz, F.
    Veisz, Laszlo
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Towards Attosecond XUV-Pump XUV-Probe Measurements in the 100-eV Region2017Ingår i: 2017 Conference on Lasers and Electro-Optics Europe / European Quantum Electronics Conference (CLEO/Europe-EQEC), IEEE, 2017Konferensbidrag (Refereegranskat)
  • 2.
    Bychkov, Vitaly
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Matyba, Piotr
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Akkerman, Vyacheslav
    Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544-5263, USA.
    Modestov, Mikhail
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Valiev, Damir
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Brodin, Gert
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Law, Chung K.
    Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544-5263, USA.
    Marklund, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Edman, Ludvig
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Speedup of doping fronts in organic semiconductors through plasma instability2011Ingår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 107, nr 1, s. 016103-016107Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The dynamics of doping transformation fronts in organic semiconductor plasma is studied for application in light-emitting electrochemical cells. We show that new fundamental effects of the plasma dynamics can significantly improve the device performance. We obtain an electrodynamic instability, which distorts the doping fronts and increases the transformation rate considerably. We explain the physical mechanism of the instability, develop theory, provide experimental evidence, perform numerical simulations, and demonstrate how the instability strength may be amplified technologically. The electrodynamic plasma instability obtained also shows interesting similarity to the hydrodynamic Darrieus-Landau instability in combustion, laser ablation, and astrophysics.

  • 3. Chen, Cong
    et al.
    Tao, Zhensheng
    Carr, Adra
    Matyba, Piotr
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik. JILA, Department of Physics, University of Colorado and National Institute of Standards and Technology, Boulder, CO 80309, United States.
    Szilvasi, Tibor
    Emmerich, Sebastian
    Piecuch, Martin
    Keller, Mark
    Zusin, Dmitriy
    Eich, Steffen
    Rollinger, Markus
    Youa, Wenjing
    Mathias, Stefan
    Thumm, Uwe
    Mavrikakis, Manos
    Aeschlimann, Martin
    Oppeneer, Peter M.
    Kapteyn, Henry
    Murnane, Margaret
    Distinguishing attosecond electron-electron scattering and screening in transition metals2017Ingår i: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 114, nr 27, s. E5300-E5307Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Electron-electron interactions are the fastest processes in materials, occurring on femtosecond to attosecond timescales, depending on the electronic band structure of the material and the excitation energy. Such interactions can play a dominant role in light-induced processes such as nano-enhanced plasmonics and catalysis, light harvesting, or phase transitions. However, to date it has not been possible to experimentally distinguish fundamental electron interactions such as scattering and screening. Here, we use sequences of attosecond pulses to directly measure electron-electron interactions in different bands of different materials with both simple and complex Fermi surfaces. By extracting the time delays associated with photoemission we show that the lifetime of photoelectrons from the d band of Cu are longer by similar to 100 as compared with those from the same band of Ni. We attribute this to the enhanced electron-electron scattering in the unfilled d band of Ni. Using theoretical modeling, we can extract the contributions of electron-electron scattering and screening in different bands of different materials with both simple and complex Fermi surfaces. Our results also show that screening influences high-energy photoelectrons (approximate to 20 eV) significantly less than low-energy photoelectrons. As a result, high-energy photoelectrons can serve as a direct probe of spin-dependent electron-electron scattering by neglecting screening. This can then be applied to quantifying the contribution of electron interactions and screening to low-energy excitations near the Fermi level. The information derived here provides valuable and unique information for a host of quantum materials.

  • 4.
    Dzwilewski, Andrzej
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Matyba, Piotr
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Edman, Ludvig
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Facile fabrication of efficient organic CMOS circuits2010Ingår i: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 114, nr 1, s. 135-140Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Organic electronic circuits based on a combination of n- and p-type transistors (so-called CMOS circuits) are attractive, since they promise the realization of a manifold of versatile and low-cost electronic devices. Here, we report a novel photoinduced transformation method, which allows for a particularly straightforward fabrication of highly functional organic CMOS circuits. A solution-deposited single-layer film, comprising a mixture of the n-type semiconductor [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and the p-type semiconductor poly-3-hexylthiophene (P3HT) in a 3:1 mass ratio, was utilized as the common active material in an array of transistors. Selected film areas were exposed to laser light, with the result that the irradiated PCBM monomers were photochemically transformed into a low-solubility and high-mobility dimeric state. Thereafter, the entire film was developed via immersion into a developer solution, which selectively removed the nonexposed, and monomeric, PCBM component. The end result was that the transistors in the exposed film areas are n-type, as dimeric PCBM is the majority component in the active material, while the transistors in the nonexposed film areas are p-type, as P3HT is the sole remaining material. We demonstrate the merit of the method by utilizing the resulting combination of n-type and p-type transistors for the realization of CMOS inverters with a high gain of ∼35.

  • 5.
    Edman, Ludvig
    et al.
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Fysik.
    Matyba, Piotr
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Fysik.
    Wågberg, Thomas
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Fysik.
    Shin, Joon Ho
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Fysik.
    Andersson, Mats
    Light-emitting Electrochemical Cells with mm-sized Electrode Gap: Controlling Light at Low Voltage and Identification of Degradation Mechanism.2008Ingår i: SPIE Photonics Europe, 2008Konferensbidrag (Övrigt vetenskapligt)
  • 6.
    Edman, Ludvig
    et al.
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Fysik.
    Shin, Joon Ho
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Fysik.
    Matyba, Piotr
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Fysik.
    Andersson, Mats R.
    Robinson, Nathaniel D.
    Direct Optical Probing of Doping Progression and Light Emission in Planar Light-Emitting Electrochemical Cells with mm-Sized Electrode Gaps.2007Ingår i: Extended abstracts – 7th International Conference on Optical Probes of π-Conjugated Polymers and Functional Self Assemblies, 2007Konferensbidrag (Övrigt vetenskapligt)
  • 7.
    Fang, Junfeng
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Matyba, Piotr
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Edman, Ludvig
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    The design and realization of flexible light-emitting electrochemical cells with record-long lifetime2009Ingår i: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 19, nr 16, s. 2671-2676Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Polymer light-emitting electrochemical cells (LECs) offer an attractive opportunity for low-cost production of functional devices in flexible and large-area configurations, but the critical drawback in comparison to competing light-emission technologies is a limited operational lifetime. Here, it is demonstrated that it is possible to improve the lifetime by straightforward and motivated means from a typical value of a few hours to more than one month of uninterrupted operation at significant brightness (>100 cd m−2) and relatively high power conversion efficiency (2 lm W−1 for orange-red emission). Specifically, by optimizing the composition of the active material and by employing an appropriate operational protocol, a desired doping structure is designed and detrimental chemical and electrochemical side reactions are identified and minimized. Moreover, the first functional flexible LEC with a similar promising device performance is demonstrated.

  • 8.
    Fang, Junfeng
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Matyba, Piotr
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Robinson, Nathaniel D.
    Department of Science and Technology, Linköping University, SE-601 74 Norrköping, Sweden.
    Edman, Ludvig
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Identifying and alleviating electrochemical side-reactions in light-emitting electrochemical cells.2008Ingår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 130, s. 4562-4568Artikel i tidskrift (Refereegranskat)
  • 9.
    Matyba, Piotr
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Polymer light-emitting electrochemical cells: Utilizing doping for generation of light2011Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

        The current implementation of conjugated polymers (“conducting plastics”) in a wide range of devices promises to bring the vision of a new generation of flexible, efficient and low-cost applications to reality. Plastic lightemitting devices in the form of polymer light-emitting diodes (PLEDs) are projected to be particularly close to the market in applications such as large area and conformable illumination panels and high-performance thin displays. However, two notable drawbacks of PLEDs are that they depend on vacuum deposition of a reactive metal for the negative electrode and that the active material must be extremely thin and uniform in thickness. As a consequence, PLEDs cannot be expected to allow for a low-cost continuous production using a roll-to-roll coating and/or printing process.

    This thesis focuses on an alternative to the PLED: A light-emitting electrochemical cell (LEC). LECs comprise a mixture of a conjugated polymer and a solid-state electrolyte as the active material positioned between two electrodes. The existence of mobile ions in the active material allows for a number of interesting attributes, both from a fundamental science and an application perspective. Importantly, the ions and the related unique operation of LECs make these devices apt for the utilization of low-cost roll-to-roll fabrication of the entire device as the electrode materials can be air stable and solution-processible and the requirement on the thickness of the active material is much less stringent than in PLEDs.

       The herein presented “basic science” studies primarily focus on the operation of LECs. It is for instance firmly established that a light-emitting p-n junction can form in-situ in a LEC device during the application of a voltage. This dynamic p-n junction exhibits some similarities, but also distinct differences, in comparison to the static p-n junctions that are exploited in crystalline inorganic semiconductor devices. We have also systematically explored the role that the constituent materials (ions, conjugated polymer, ionic solvent, and electrode material) can have on the performance of LECs, and two of the more important findings are that the concentration of ions can influence the doping structure in a motivated fashion and that it is critically important to consider the electrochemical stability window of the constituent materials in order to attain stable device operation.

       With this knowledge at hand, we have executed a number of more “applied science” studies, where we have used the acquired information from the basic-science studies for the rational design of improved devices. We have demonstrated LEC devices with significantly improved device performance, as exemplified by an orange-red device that emitted significant light (> 100 cd/m2) for more than one month of uninterrupted operation, and a yellow-green device that emitted significant light for 25 days at a low voltage of 4 V and at relatively high efficiency (6 lm/W). Finally, we have conceptualized and realized a solely solution-processed and metal-free LEC comprising graphene as the negative electrode and the conducting polymer PEDOT-PSS as the positive electrode. This type of devices represents a paradigm shift in the field of solid-state lighting as they demonstrate that it is possible to fabricate an entire light-emitting device from solution-processible and “green” carbon-based materials in a process that is akin to printing.

  • 10.
    Matyba, Piotr
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Andersson, Mats R.
    Department of Polymer Technology, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.
    Edman, Ludvig
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    On the desired properties of a conjugated polymer-electrolyte blend in a light-emitting electrochemical cell2008Ingår i: Organic electronics, ISSN 1566-1199, E-ISSN 1878-5530, Vol. 9, nr 5, s. 699-710Artikel i tidskrift (Refereegranskat)
  • 11.
    Matyba, Piotr
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Maturova, Klara
    Eindhoven University of Technology.
    Kemerink, Martijn
    Eindhoven University of Technology.
    Robinson, Nathaniel
    Department of Physics, Chemistry and Biology, Linköping University, Sweden .
    Edman, Ludvig
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    The dynamic organic p-n junction2009Ingår i: Nature Materials, ISSN 1476-1122, E-ISSN 1476-4660, Vol. 8, nr 8, s. 672-676Artikel i tidskrift (Refereegranskat)
  • 12.
    Matyba, Piotr
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Yamaguchi, Hisato
    Rutgers University.
    Eda, Goki
    Rutgers University.
    Chhowalla, Manish
    Rutgers University.
    Edman, Ludvig
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Robinson, Nathaniel D.
    Linköpings universitet.
    Graphene and mobile ions: the key to all-plastic, solution-processed light-emitting devices2010Ingår i: ACS Nano, ISSN 1936-0851, Vol. 4, nr 2, s. 637-642Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The emerging field of “organic” or “plastic” electronics has brought low-voltage, ultrathin, and energy-efficient lighting and displays to market as organic light-emitting diode (OLED) televisions and displays in cameras and mobile phones. Despite using carbon-based materials as the light-emitting layer, previous efficient organic electronic light-emitting devices have required at least one metal electrode. Here, we utilize chemically derived graphene for the transparent cathode in an all-plastic sandwich-structure device, similar to an OLED, called a light-emitting electrochemical cell (LEC). Using a screen-printable conducting polymer as a partially transparent anode and a micrometer-thick active layer solution-deposited from a blend of a light-emitting polymer and a polymer electrolyte, we demonstrate a light-emitting device based solely on solution-processable carbon-based materials. Our results demonstrate that low-voltage, inexpensive, and efficient light-emitting devices can be made without using metals. In other words, electronics can truly be “organic”.

  • 13.
    Modestov, Mikhail
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Bychkov, Vitaly
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Brodin, Gert
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Valiev, Damir
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Marklund, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Matyba, Piotr
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Edman, Ludvig
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Model of the electrochemical conversion of an undoped organic semiconductor film to a doped conductor film.2010Ingår i: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 81, nr 8, s. 081203(R)-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We develop a model describing the electrochemical conversion of an organic semiconductor (specifically, the active material in a light-emitting electrochemical cell) from the undoped nonconducting state to the doped conducting state. The model, an extended Nernst-Planck-Poisson model, takes into account both strongly concentration-dependent mobility and diffusion for the electronic charge carriers and the Nernst equation in the doped conducting regions. The standard Nernst-Planck-Poisson model is shown to fail in its description of the properties of the doping front. Solving our extended model numerically, we demonstrate that doping front progression in light-emitting electrochemical cells can be accurately described.

  • 14. Robinson, Nate D.
    et al.
    Fang, Junfeng
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Fysik.
    Matyba, Piotr
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Fysik.
    Edman, Ludvig
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Fysik.
    Electrochemical doping during light emission in polymer light-emitting electrochemical cells2008Ingår i: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 78, nr 24, s. 245202-Artikel i tidskrift (Refereegranskat)
  • 15.
    Sandström, Andreas
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Matyba, Piotr
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Edman, Ludvig
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Yellow-green light-emitting electrochemical cells with long lifetime and high efficiency2010Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 96, nr 5, s. 053303-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

     We show that the electrochemical stability window of the constituent components in light-emitting electrochemical cells (LECs), e.g., the electrolyte, should be considered in order to minimize undesired side reactions. By designing and operating LECs in accordance with straightforward principles, we demonstrate sandwich cells that turn on fast at room temperature (<2 s), and which emit significant yellow-green light (>100 cd/m2) during 25 days of uninterrupted operation at low voltage (<4 V) and high power conversion efficacy ~6 lm/W. We further demonstrate that it is possible to attain balanced p- and n-type doping and a centered p-n junction in such planar LECs based on the conjugated polymer “superyellow.”

  • 16.
    Sandström, Andreas
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Matyba, Piotr
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Inganäs, Olle
    Linköpings universitet.
    Edman, Ludvig
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Separating ion and and electron transport: the bi-layer light-emitting electrochemical cell2010Ingår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 132, nr 19, s. 6646-6647Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The current generation of polymer light-emitting electrochemical cells (LECs) suffers from insufficient stability during operation. One identified culprit is the active material, which comprises an intimate blend between an ion-conducting electrolyte and an electron-transporting conjugated polymer, as it tends to undergo phase separation during long-term operation and the intimate contact between the ion- and electron-transporting components provokes side reactions. To address these stability issues, we present here a bilayer LEC structure in which the electrolyte is spatially separated from the conjugated polymer. We demonstrate that employing this novel device structure, with its clearly separated ion- and electron-transport paths, leads to distinctly improved LEC performance in the form of decreased turn-on time and improved light emission. We also point out that it will allow for the utilization of combinations of active materials having mutually incompatible solubilities.

  • 17.
    Shin, Joon Ho
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Matyba, Piotr
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Robinson, Nathaniel D.
    Department of Science and Technology, Linköpings Universitet, SE-601 74 Norrköping, Sweden.
    Edman, Ludvig
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    The influence of electrodes on the performance of light-emitting electrochemical cells2007Ingår i: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 52, nr 23, s. 6456–6462-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We demonstrate that the electrochemical properties of the electrode material can have a dramatic impact on the performance of light-emitting electrochemical cells (LECs). Specifically, we report results from planar wide-gap LECs containing a blend of poly(2-methoxy,5-(2’-ethylhexyloxy)-p-phenylene vinylene) (MEH-PPV), poly(ethylene oxide) and LiCF3SO3 as the active material. We find that Au electrodes are preferable over Al electrodes, since Au-electrode devices exhibit fast turn-on (i.e., p-n junction formation time) and clearly visible light emission during operation at 5 V and 360 K, while Al-electrode devices exhibit slow turn-on (due to a delayed onset of p-doping progression) and no visible light emission. These results are rationalized with a cyclic voltammetry study, which demonstrates that Al is oxidized at a lower potential than the p-doping (oxidation) potential of MEH-PPV, while Au is electrochemically inert over the entire voltage range spanned by the p- and n-doping potentials of MEH-PPV. Consequently, the oxidation charge injected into Al-electrode devices results in a combination of p-doping of MEH-PPV and formation of Al ions. The latter process is undesired since it results in a slow turn-on time and quenched light emission. Finally, we find that planar LECs in a bottom-electrode configuration exhibit a faster turn-on time than identical devices with the electrodes on top of the active material.

  • 18.
    van Reenen, Stephan
    et al.
    Eindhoven University of Technology.
    Matyba, Piotr
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Dzwilewski, Andrzej
    Eindhoven University of Technology.
    Jenssen, Rene A.J.
    Eindhoven University of Technology.
    Edman, Ludvig
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Kemerink, Martijn
    Eindhoven University of Technology.
    Salt concentration effects in planar light-emitting electrochemical cellsArtikel i tidskrift (Refereegranskat)
  • 19.
    van Reenen, Stephan
    et al.
    Eindhoven University of Technology.
    Matyba, Piotr
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Dzwilewski, Andrzej
    Eindhoven University of Technology.
    Rene A. J., Jenssen
    Eindhoven University of Technology.
    Edman, Ludvig
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Martijn, Kemerink
    Eindhoven University of Technology.
    A unifying model for the operation of light-emitting electrochemical cells2010Ingår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 132, nr 39, s. 13776-13781Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The application of doping in semiconductors plays a major role in the high performances achieved to date in inorganic devices. In contrast, doping has yet to make such an impact in organic electronics. One organic device that does make extensive use of doping is the light-emitting electrochemical cell (LEC), where the presence of mobile ions enables dynamic doping, which enhances carrier injection and facilitates relatively large current densities. The mechanism and effects of doping in LECs are, however, still far from being fully understood, as evidenced by the existence of two competing models that seem physically distinct: the electrochemical doping model and the electrodynamic model. Both models are supported by experimental data and numerical modeling. Here, we show that these models are essentially limits of one master model, separated by different rates of carrier injection. For ohmic nonlimited injection, a dynamic p−n junction is formed, which is absent in injection-limited devices. This unification is demonstrated by both numerical calculations and measured surface potentials as well as light emission and doping profiles in operational devices. An analytical analysis yields an upper limit for the ratio of drift and diffusion currents, having major consequences on the maximum current density through this type of device.

  • 20.
    Wågberg, Thomas
    et al.
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Fysik.
    Hania, Ralph
    Robinson, Nate
    Shin, Joon Ho
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Fysik.
    Matyba, Piotr
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Fysik.
    Edman, Ludvig
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Fysik.
    On the Limited Operational Lifetime of Light-Emitting Electrochemical Cells2008Ingår i: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 20, nr 9, s. 1744-1749Artikel i tidskrift (Refereegranskat)
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