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  • 151.
    Broitman, Esteban
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Yousuf Soomro, Muhammad
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Lu, Jun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Nanoscale piezoelectric response of ZnO nanowires measured using a nanoindentation technique2013Ingår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 15, nr 26, s. 11113-11118Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report the piezoelectric properties of ZnO nanowires (NWs) obtained by using a nanoindenter with a conductive boron-doped diamond tip. The direct piezoelectric effect was measured by performing nanoindentations under load control, and the generated piezoelectric voltage was characterized as a function of the applied loads in the range 0.2-6 mN. The converse piezoelectric effect was measured by applying a DC voltage to the sample while there was a low applied force to allow the tip being always in physical contact with the NWs. Vertically aligned ZnO NWs were grown on inexpensive, flexible, and disposable paper substrates using a template-free low temperature aqueous chemical growth method. When using the nanoindenter to measure the direct piezoelectric effect, piezopotential values of up to 26 mV were generated. Corresponding measurement of the converse piezoelectric effect gave an effective piezoelectric coefficient d(33)(eff) of similar to 9.2 pm V-1. The ZnO NWs were also characterized using scanning electron microscopy, X-ray diffraction, and high-resolution transmission electron microscopy. The new nanoindentation approach provides a straightforward method to characterize piezoelectric material deposited on flexible and disposable substrates for the next generation of nanodevices.

  • 152.
    Brooke, Robert
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska fakulteten.
    Edberg, Jesper
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Iandolo, Donata
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska fakulteten. Ecole Natl Super Mines, France.
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Crispin, Xavier
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Engquist, Isak
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Controlling the electrochromic properties of conductive polymers using UV-light2018Ingår i: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 6, nr 17, s. 4663-4670Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The phenomenon of electrochromism in conductive polymers is well known and has been exploited in many scientific reports. Using a newly developed patterning technique for conductive polymers, we manufactured high-resolution electrochromic devices from the complementary polymers PEDOT and polypyrrole. The technique, which combines UV-light exposure with vapor phase polymerization, has previously only been demonstrated with the conductive polymer PEDOT. We further demonstrated how the same technique can be used to control the optical properties and the electrochromic contrast in these polymers. Oxidant exposure to UV-light prior to vapor phase polymerization showed a reduction in polymer electrochromic contrast allowing high-resolution (100 mu m) patterns to completely disappear while applying a voltage bias due to their optical similarity in one redox state and dissimilarity in the other. This unique electrochromic property enabled us to construct devices displaying images that appear and disappear with the change in applied voltage. Finally, a modification of the electrochromic device architecture permitted a dual image electrochromic device incorporating patterned PEDOT and patterned polypyrrole on the same electrode, allowing the switching between two different images.

  • 153.
    Brooke, Robert
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten. University of S Australia, Australia.
    Fabretto, Manrico
    University of S Australia, Australia.
    Krasowska, Marta
    University of S Australia, Australia.
    Talemi, Pejman
    University of S Australia, Australia; University of Adelaide, Australia.
    Pering, Samuel
    University of Bath, England.
    Murphy, Peter J.
    University of S Australia, Australia.
    Evans, Drew
    University of S Australia, Australia.
    Organic energy devices from ionic liquids and conducting polymers2016Ingår i: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 4, nr 7, s. 1550-1556Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The use of smart technologies in our daily lives, from smartphones to auto-dimming windows to touch sensors, has become pervasive. With growing desire for these devices to be conformable and flexible, traditional materials are being replaced to create a class of products known as active organic electronic devices (OEDs). These new devices owe their ability to switch electrical and/or optical function to the intimate interaction between an inherently conducting polymer and electrolyte, typically an ionic liquid. Herein, we provide the first observations that specific ionic liquids can reduce or oxidise conducting polymers upon intimate contact in the absence of any electrical stimuli. The ability to reduce or oxidise the inherently conducting polymer depends on the cation and anion pair within the ionic liquid. Extending the utility of this phenomenon is made by fabricating OEDs such as prototype fuel cells, supercapacitors and smart windows.

  • 154.
    Brooke, Robert
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska fakulteten.
    Franco Gonzalez, Felipe
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Wijeratne, Kosala
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Pavlopoulou, Eleni
    Univ Bordeaux, France.
    Galliani, Daniela
    Univ Milano Bicocca, Italy.
    Liu, Xianjie
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska fakulteten.
    Valiollahi Bisheh, Roudabeh
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska fakulteten.
    Zozoulenko, Igor
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Crispin, Xavier
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Vapor phase synthesized poly(3,4-ethylenedioxy-thiophene)-trifluoromethanesulfonate as a transparent conductor material2018Ingår i: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 6, nr 43, s. 21304-21312Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Inorganic transparent conductive oxides have dominated the market as transparent electrodes due to their high conductivity and transparency. Here, we report the fabrication and optimization of the synthesis of poly(3,4-ethylenedioxythiophene) trifluoromethanesulfonate via vapor phase polymerization for the potential replacement of such inorganic materials. The parameters and conditions of the polymerization were investigated and an electrical conductivity of 3800 S cm(-1) and 4500 S cm(-1) after acid treatment were obtained while maintaining an absorbance similar to that of commercial indium tin oxide. This increase in electrical conductivity was rationalized experimentally and theoretically to an increase in the oxidation level and a higher order of crystallinity which does not disrupt the pi-pi stacking of PEDOT chains.

  • 155.
    Brooke, Robert
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Mitraka, Evangelia
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Sardar, Samim
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Sandberg, Mats
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten. Acreo Swedish ICT, SE-601 74 Norrköping, Sweden.
    Sawatdee, Anurak
    Acreo Swedish ICT, SE-601 74 Norrköping, Sweden.
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Crispin, Xavier
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Jonsson, Magnus P.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Infrared electrochromic conducting polymer devices2017Ingår i: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 5, nr 23, s. 5824-5830Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) is well known for its electrochromic properties in the visible region. Less focus has been devoted to the infrared (IR) wavelength range, although tunable IR properties could enable a wide range of novel applications. As an example, modern day vehicles have thermal cameras to identify pedestrians and animals in total darkness, but road and speed signs cannot be easily visualized by these imaging systems. IR electrochromism could enable a new generation of dynamic road signs that are compatible with thermal imaging, while simultaneously providing contrast also in the visible region. Here, we present the first metal-free flexible IR electrochromic devices, based on PEDOT:Tosylate as both the electrochromic material and electrodes. Lateral electrochromic devices enabled a detailed investigation of the IR electrochromism of thin PEDOT:Tosylate films, revealing large changes in their thermal signature, with effective temperature changes up to 10 [degree]C between the oxidized (1.5 V) and reduced (-1.5 V) states of the polymer. Larger scale (7 [times] 7 cm) vertical electrochromic devices demonstrate practical suitability and showed effective temperature changes of approximately 7 [degree]C, with good optical memory and fast switching (1.9 s from the oxidized state to the reduced state and 3.3 s for the reversed switching). The results are highly encouraging for using PEDOT:Tosylate for IR electrochromic applications.

  • 156.
    Bubnova, Olga
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Thermoelectric properties of conducting polymers2013Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    According to different sources, from forty to sixty percent of the overall energy generated in the world today is squandered in waste heat. The existing energy conversion technologies are either close to their efficiency limits or too costly to justify their implementation. Therefore, the development of new technological approaches for waste heat recovery is highly demanded. The field of thermoelectrics can potentially provide an inexpensive, clean and efficient solution to waste heat underutilization, given that a new type of thermoelectric materials capable of meeting those requirements are available.

    This thesis reports on strategies to optimize a thermoelectric efficiency (ZT) of conducting polymers, more specifically poly(3,4-ethylenedioxythiophene) (Pedot). Conducting polymers constitute a special class of semiconductors characterized by low thermal conductivity as well as electrical conductivity and thermopower that can be readily modified by doping in order to achieve the best combination of thermoelectric parameters. Conducting polymers that have never previously been regarded as hypothetically compatible for thermoelectric energy conversion, can exhibit promising thermoelectric performance at moderate temperatures, which is a sought-after quality for waste heat recovery. A rather substandard thermoelectric efficiency of Pedot-Pss can be markedly improved by various secondary dopants whose addition usually improves polymer’s morphology accompanied by a drastic increase in electrical conductivity and, consequently, in ZT. In order to enable further enhancement in thermoelectric properties, the optimization of the charge carrier concentration is commonly used. The oxidation level of Pedot-Pss can be precisely controlled by electrochemical doping resulting in a tenfold increase of ZT. In contrast to Pedot-Pss, another conducting polymer Pedot-Tos exhibits superior thermoelectric performance even without secondary doping owning to its partially crystalline nature that allows for an improved electronic conduction. With the aid of a strong electron donor, positively doped Pedot-Tos gets partially reduced reaching the optimum oxidation state at which its thermoelectric efficiency is just four times smaller than that of Be2Te3 and the highest among all stable conducting polymers. The downsides associated with chemical doping of Pedot-Tos such as doping inhomogeneity or chemical dopants air sensitivity can be surmounted if the doping level of Pedot-Tos is controlled by acidity/basicity of the polymer. This approach yields similar maximum thermoelectric efficiency but does not necessitate inert conditions for sample preparation. Optimized Pedot-Tos/Pedot-Pss can be functionalized as a p-type material in organic thermogenerators (OTEG) to power low energy electronic devices. If printed on large areas, OTEGs could be used as an alternative technique for capturing heat discarded by industrial processes, households, transportation sector or any natural heat sources for electricity production.

    Delarbeten
    1. Towards polymer-based organic thermoelectric generators
    Öppna denna publikation i ny flik eller fönster >>Towards polymer-based organic thermoelectric generators
    2012 (Engelska)Ingår i: Energy & Environmental Science, ISSN 1754-5692, E-ISSN 1754-5706, Vol. 5, nr 11, s. 9345-9362Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    In response to the thread of environmental and ecological degradation along with projected fossil fuel depletion the active search for efficient renewable energy conversion technologies has been attempted in various research areas including the field of thermoelectrics. Despite the availability of considerable amounts of waste and natural heat stored in warm fluids (andlt;250 degrees C) a lack of environmentally friendly materials with high natural abundance, low manufacturing cost and high thermoelectric efficiency impedes the widespread use of thermoelectric generators for energy harvesting on a large scale. In this perspective, we examine the possibility of using organic conducting polymers in thermoelectric applications. We provide an overview of the background and the key concepts of organic thermoelectrics and illustrate some of the first prototypes of polymer-based organic thermoelectric generators.

    Ort, förlag, år, upplaga, sidor
    Royal Society of Chemistry, 2012
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-85293 (URN)10.1039/c2ee22777k (DOI)000310006200015 ()
    Anmärkning

    Funding Agencies|European Research Council||Swedish foundation for strategic research||Knut and Alice Wallenberg foundation||Swedish Energy Agency||Advanced Functional Materials Center at Linkoping University||

    Tillgänglig från: 2012-11-19 Skapad: 2012-11-15 Senast uppdaterad: 2018-08-31
    2. Tuning the Thermoelectric Properties of Conducting Polymers in an Electrochemical Transistor
    Öppna denna publikation i ny flik eller fönster >>Tuning the Thermoelectric Properties of Conducting Polymers in an Electrochemical Transistor
    2012 (Engelska)Ingår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 134, nr 40, s. 16456-16459Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    While organic field-effect transistors allow the investigation of interfacial charge transport at the semiconductor-dielectric interface, an electrochemical transistor truly modifies the oxidation level and conductivity throughout the bulk of an organic semiconductor. In this work, the thermoelectric properties of the bulk of the conducting polymer poly(3,4-ethylenedioxythiophene) -poly(styrene sulfonate) were controlled electrically by varying the gate voltage. In light of the growing interest in conducting polymers as thermoelectric generators, this method provides an easy tool to study the physics behind the thermoelectric properties and to optimize polymer thermoelectrics.

    Ort, förlag, år, upplaga, sidor
    American Chemical Society, 2012
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-85195 (URN)10.1021/ja305188r (DOI)000309566400003 ()
    Anmärkning

    Funding Agencies|Swedish Foundation for Strategic Research||Knut and Alice Wallenberg Foundation||Swedish Energy Agency||Advanced Functional Materials Center at Linkoping University||ERC Starting Grant||

    Tillgänglig från: 2012-11-09 Skapad: 2012-11-09 Senast uppdaterad: 2017-12-07
    3. Optimization of the thermoelectric figure of merit in the conducting polymer poly(3,4-ethylenedioxythiophene)
    Öppna denna publikation i ny flik eller fönster >>Optimization of the thermoelectric figure of merit in the conducting polymer poly(3,4-ethylenedioxythiophene)
    Visa övriga...
    2011 (Engelska)Ingår i: NATURE MATERIALS, ISSN 1476-1122, Vol. 10, nr 6, s. 429-433Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Thermoelectric generators (TEGs) transform a heat flow into electricity. Thermoelectric materials are being investigated for electricity production from waste heat (co-generation) and natural heat sources. For temperatures below 200 degrees C, the best commercially available inorganic semiconductors are bismuth telluride (Bi2Te3)-based alloys, which possess a figure of merit ZT close to one(1). Most of the recently discovered thermoelectric materials with ZT andgt; 2 exhibit one common property, namely their low lattice thermal conductivities(2,3). Nevertheless, a high ZT value is not enough to create a viable technology platform for energy harvesting. To generate electricity from large volumes of warm fluids, heat exchangers must be functionalized with TEGs. This requires thermoelectric materials that are readily synthesized, air stable, environmentally friendly and solution processable to create patterns on large areas. Here we show that conducting polymers might be capable of meeting these demands. The accurate control of the oxidation level in poly(3,4-ethylenedioxythiophene) (PEDOT) combined with its low intrinsic thermal conductivity (lambda = D 0.37W m(-1) K-1) yields a ZT = 0.25 at room temperature that approaches the values required for efficient devices.

    Ort, förlag, år, upplaga, sidor
    Nature Publishing Group, 2011
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-68783 (URN)10.1038/nmat3012 (DOI)000290855100016 ()
    Tillgänglig från: 2011-06-08 Skapad: 2011-06-07 Senast uppdaterad: 2017-02-03
  • 157.
    Bubnova, Olga
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Crispin, Xavier
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Ph effect on thermoelectric properties of poly-(3,4-ethylenedioxythiophene):tosylateManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Abstract not available.

  • 158.
    Bubnova, Olga
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Crispin, Xavier
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Tuning the Thermoelectric Properties of Conducting Polymers in an Electrochemical Transistor2012Ingår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 134, nr 40, s. 16456-16459Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    While organic field-effect transistors allow the investigation of interfacial charge transport at the semiconductor-dielectric interface, an electrochemical transistor truly modifies the oxidation level and conductivity throughout the bulk of an organic semiconductor. In this work, the thermoelectric properties of the bulk of the conducting polymer poly(3,4-ethylenedioxythiophene) -poly(styrene sulfonate) were controlled electrically by varying the gate voltage. In light of the growing interest in conducting polymers as thermoelectric generators, this method provides an easy tool to study the physics behind the thermoelectric properties and to optimize polymer thermoelectrics.

  • 159.
    Bubnova, Olga
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Crispin, Xavier
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Towards polymer-based organic thermoelectric generators2012Ingår i: Energy & Environmental Science, ISSN 1754-5692, E-ISSN 1754-5706, Vol. 5, nr 11, s. 9345-9362Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In response to the thread of environmental and ecological degradation along with projected fossil fuel depletion the active search for efficient renewable energy conversion technologies has been attempted in various research areas including the field of thermoelectrics. Despite the availability of considerable amounts of waste and natural heat stored in warm fluids (andlt;250 degrees C) a lack of environmentally friendly materials with high natural abundance, low manufacturing cost and high thermoelectric efficiency impedes the widespread use of thermoelectric generators for energy harvesting on a large scale. In this perspective, we examine the possibility of using organic conducting polymers in thermoelectric applications. We provide an overview of the background and the key concepts of organic thermoelectrics and illustrate some of the first prototypes of polymer-based organic thermoelectric generators.

  • 160.
    Bubnova, Olga
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Khan, Zia Ullah
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Wang, Hui
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Braun, Slawomir
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska högskolan.
    Evans, Drew R
    University of South Australia, Mawson Institute, Mawson Lakes 5095, Australia.
    Fabretto, Manrico
    University of South Australia, Mawson Institute, Mawson Lakes 5095, Australia.
    Hojati-Talemi, Pejman
    University of South Australia, Mawson Institute, Mawson Lakes 5095, Australia.
    Dagnelund, Daniel
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Funktionella elektroniska material. Linköpings universitet, Tekniska högskolan.
    Arlin, Jean-Baptiste
    Free University of Brussels, Laboratoire de Chimie des Polymères, CP 206/1, Boulevard du Triomphe, 1050 Bruxelles, Belgium.
    Geerts, Yves H.
    Free University of Brussels, Laboratoire de Chimie des Polymères, CP 206/1, Boulevard du Triomphe, 1050 Bruxelles, Belgium.
    Desbief, Simon
    University of Mons, Laboratoire de chimie des materiaux nouveaux, Place du Parc 20, 7000 Mons, Belgium.
    Breiby, Dag W.
    Norwegian University of Science and Technology (NTNU), Department of Physics, Høgskoleringen 5, 7491 Trondheim, Norway.
    Andreasen, Jens W.
    Technical University of Denmark, Department of Energy Conversion and Storage, Frederiksborgvej 399, 4000 Roskilde, Denmark.
    Lazzaroni, Roberto
    University of Mons, Laboratoire de chimie des materiaux nouveaux, Place du Parc 20, 7000 Mons, Belgium.
    Chen, Weimin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Funktionella elektroniska material. Linköpings universitet, Tekniska högskolan.
    Zozoulenko, Igor
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Fahlman, Mats
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Murphy, Peter J.
    University of South Australia, Mawson Institute, Mawson Lakes 5095, Australia.
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Crispin, Xavier
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Corrigendum: Semi-metallic polymers2014Ingår i: Nature Materials, ISSN 1476-1122, E-ISSN 1476-4660, Vol. 13, s. 662-662Artikel i tidskrift (Refereegranskat)
  • 161.
    Bubnova, Olga
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Ullah Khan, Zia
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Malti, Abdellah
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Braun, Slawomir
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska högskolan.
    Fahlman, Mats
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska högskolan.
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Crispin, Xavier
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Optimization of the thermoelectric figure of merit in the conducting polymer poly(3,4-ethylenedioxythiophene)2011Ingår i: NATURE MATERIALS, ISSN 1476-1122, Vol. 10, nr 6, s. 429-433Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Thermoelectric generators (TEGs) transform a heat flow into electricity. Thermoelectric materials are being investigated for electricity production from waste heat (co-generation) and natural heat sources. For temperatures below 200 degrees C, the best commercially available inorganic semiconductors are bismuth telluride (Bi2Te3)-based alloys, which possess a figure of merit ZT close to one(1). Most of the recently discovered thermoelectric materials with ZT andgt; 2 exhibit one common property, namely their low lattice thermal conductivities(2,3). Nevertheless, a high ZT value is not enough to create a viable technology platform for energy harvesting. To generate electricity from large volumes of warm fluids, heat exchangers must be functionalized with TEGs. This requires thermoelectric materials that are readily synthesized, air stable, environmentally friendly and solution processable to create patterns on large areas. Here we show that conducting polymers might be capable of meeting these demands. The accurate control of the oxidation level in poly(3,4-ethylenedioxythiophene) (PEDOT) combined with its low intrinsic thermal conductivity (lambda = D 0.37W m(-1) K-1) yields a ZT = 0.25 at room temperature that approaches the values required for efficient devices.

  • 162.
    Bubnova, Olga
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Ullah Khan, Zia
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Wang, Hui
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Braun, Slawomir
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska högskolan.
    Evans, Drew R.
    University of S Australia, Australia .
    Fabretto, Manrico
    University of S Australia, Australia .
    Hojati-Talemi, Pejman
    University of S Australia, Australia .
    Dagnelund, Daniel
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Funktionella elektroniska material. Linköpings universitet, Tekniska högskolan.
    Arlin, Jean-Baptiste
    University of Libre Brussels, Belgium .
    Geerts, Yves H.
    University of Libre Brussels, Belgium .
    Desbief, Simon
    University of Mons, Belgium .
    Breiby, Dag W.
    Norwegian University of Science and Technology NTNU, Norway .
    Andreasen, Jens W.
    Technical University of Denmark, Denmark .
    Lazzaroni, Roberto
    University of Mons, Belgium .
    Chen, Weimin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Funktionella elektroniska material. Linköpings universitet, Tekniska högskolan.
    Zozoulenko, Igor
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Fahlman, Mats
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska högskolan.
    Murphy, Peter J.
    University of S Australia, Australia .
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Crispin, Xavier
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Semi-metallic polymers2014Ingår i: Nature Materials, ISSN 1476-1122, E-ISSN 1476-4660, Vol. 13, nr 2, s. 190-194Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Polymers are lightweight, flexible, solution-processable materials that are promising for low-cost printed electronics as well as for mass-produced and large-area applications. Previous studies demonstrated that they can possess insulating, semiconducting or metallic properties; here we report that polymers can also be semi-metallic. Semi-metals, exemplified by bismuth, graphite and telluride alloys, have no energy bandgap and a very low density of states at the Fermi level. Furthermore, they typically have a higher Seebeck coefficient and lower thermal conductivities compared with metals, thus being suitable for thermoelectric applications. We measure the thermoelectric properties of various poly( 3,4-ethylenedioxythiophene) samples, and observe a marked increase in the Seebeck coefficient when the electrical conductivity is enhanced through molecular organization. This initiates the transition from a Fermi glass to a semi-metal. The high Seebeck value, the metallic conductivity at room temperature and the absence of unpaired electron spins makes polymer semi-metals attractive for thermoelectrics and spintronics.

  • 163.
    Bubnova, Olga
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Ullah Khan, Zia
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Wang, Hui
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Dagnelund, Daniel
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Funktionella elektroniska material. Linköpings universitet, Tekniska högskolan.
    Arlin, Jean-Baptiste
    Free University of Brussels Laboratoire de Chimie des Polymères, Bruxelles, Belgium.
    Geerts, Yves
    Free University of Brussels Laboratoire de Chimie des Polymères, Bruxelles, Belgium.
    Desbief, Simon
    University of Mons Laboratoire de chimie des materiaux nouveaux, Mons, Belgium.
    Breiby, Dag W.
    Department of Physics, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
    Andreasen, Jens W.
    Imaging and Structural Analysis Programme, Department of Energy Conversion and Storage, Technical University of Denmark, Roskilde, Denmark.
    Lazzaroni, Roberto
    University of Mons Laboratoire de chimie des materiaux nouveaux, Mons, Belgium.
    Zozoulenko, Igor
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Crispin, Xavier
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Advantageous thermoelectric properties of a semimetallic polymerManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Thermoelectric generation potentially holds a solution for waste heat recovery issues provided that the availability of inexpensive, biodegradable and highly efficient thermoelectric materials is insured in the near future. Plastic thermoelectrics could successfully comply with the said requirements if the thermoelectric efficiency (ZT) of conducting polymers was higher. However, given the novelty of the subject, at present there are no clear guidelines for ZT optimization in this class of materials. The most important piece of information that is currently missing is the description of a specific electronic makeup that conducting polymers must possess in order to enable good thermoelectric performance. In the present study the thermoelectric properties of poly(3,4-ethylenedioxythiophene) derivatives with two types of counterions, i.e. poly(styrenesulfonate) (PSS) and tosylate (Tos) are evaluated. A striking variation in their thermoelectric performance is attributed to structural and morphological differences between two polymers that manifest itself in dissimilar charge transport mechanism. The superior properties of PEDOT-Tos presumably originate from a high degree of crystallinity and structural order that predetermines the tendency for bipolaron band formation. Unlike polaronic PEDOT-PSS with slowly varying density of localized states (DOS) near the Fermi level (EF), the DOS in PEDOT-Tos is characterized by higher asymmetry and higher charge carrier density at EF (similar to semimetals), which allows for higher thermopower and electrical conductivity. Therefore, we conclude that the polymers with semimetallic electronic makeup are expected to exhibit promising thermoelectric properties with bigger variation in thermopower upon doping.

  • 164.
    Börjesson, Sara I.
    et al.
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Cellbiologi. Linköpings universitet, Hälsouniversitetet.
    Englund, Ulrika H.
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Cellbiologi. Linköpings universitet, Hälsouniversitetet.
    Asif, Muhammad H.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Elinder, Fredrik
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Cellbiologi. Linköpings universitet, Hälsouniversitetet.
    Intracellular potassium (K+) concentration decrease is not obligatory for apoptosis2011Ingår i: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 286, nr 46, s. 39823-39828Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    K+ efflux is observed as an early event in the apoptotic process in various cell types. Loss of intracellular K+ and subsequent reduction in ionic strength is suggested to release the inhibition of proapoptotic caspases. In this work, a new K+-specific microelectrode was used to study possible alterations in intracellular K+ in Xenopus laevis oocytes during chemically induced apoptosis. The accuracy of the microelectrode to detect changes in intracellular K+ was verified with parallel electrophysiological measurements within the same cells. In concordance with previous studies on other cell types, apoptotic stimuli reduced the intracellular K+ concentration in Xenopus oocytes and increased caspase-3 activity. The reduction in intracellular K+ was prevented by dense expression of voltage-gated K (Kv) channels. Despite this, the caspase-3 activity was increased similarly in Kv channel expressing oocytes as in oocytes not expressing Kv channels. Thus, in Xenopus oocytes caspase-3 activity is not dependent on the intracellular concentration of K+.

  • 165.
    Campana, Alessandra
    et al.
    CNR-ISMN, Bologna, Italy; University of Bologna, Italy .
    Cramer, Tobias
    CNR-ISMN, Bologna, Italy.
    Simon, Daniel
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan. null.
    Biscarini, Fabio
    CNR-ISMN, Bologna, Italy; University of Modena and Reggio Emilia, Italy .
    Electrocardiographic recording with conformable organic electrochemical transistor fabricated on resorbable bioscaffold2014Ingår i: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 26, nr 23, s. 3874-3878Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Organic electrochemical transistors are fabricated on a poly(L-lactide-co-glycolide) substrate. Fast and sensitive performance of the transistors allows recording of the electrocardiogram. The result paves the way for new types of bioelectronic interfaces with reduced invasiveness due to bioresorption and soft mechanical properties.

  • 166.
    Carlsson, Jacob
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Isolated WiFi Environments2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    WiFi is becoming common in households and digital devices needs to support it. At the same time the devices are getting smaller and the Ethernet port may seem superfluous. When testing these devices the test environment needs to be able to provide WiFi connectivity. The tests may be focused on testing WiFi but it could also be the only network connectivity and thus needs to be very reliable. With a large number of devices in a small physical area a normal WiFi setup would have a density of devices that is too high for today’s1 WiFi standards. A combination of wired physical medium and physical isolation was considered.

  • 167.
    Carstenen, Anna-Karin
    et al.
    Ingenjörshögskolan, Jönköping.
    Bernhard, Jonte
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    How key concepts can make students cope with liminality2010Konferensbidrag (Refereegranskat)
  • 168.
    Carstensen, Anna-Karin
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Connect: Modelling Learning to Facilitate Linking Models and the Real World trough Lab-Work in Electric Circuit Courses for Engineering Students2013Doktorsavhandling, monografi (Övrigt vetenskapligt)
    Abstract [sv]

    En stående fråga som lärare i naturvetenskapliga och tekniska utbildningar ställer är varför elever och studenter inte kopplar samman kunskaper från teoretiska kursmoment med den verklighet som möts vid laborationerna. Ett vanligt syfte med laborationer är att åstadkomma länkar mellan teori och verklighet, men dessa uteblir ofta.

    Många gånger används avancerade matematiska modeller och grafiska representationer, vilka studenterna lärt sig i tidigare kurser, men de har sällan eller aldrig tillämpat dessa kunskaper i andra ämnen. En av dessa matematiska hjälpmedel är Laplacetransformen, som främst används för att lösa differentialekvationer, och åskådliggöra transienta förlopp i ellära eller reglerteknik. På många universitet anses Laplacetransformen numera för svår för studenterna på kortare ingenjörsutbildningar, och kurser eller kursmoment som kräver denna har strukits ut utbildningsplanerna. Men, är det för svårt, eller beror det bara på hur man presenterar Laplacetransformen?

    Genom att låta studenterna arbeta parallellt med matematiken och de laborativa momenten, under kombinerade lab-lektionspass, och inte vid separata lektioner och laborationer, samt genom att variera övningsexemplen på ett mycket systematiskt sätt, enligt variationsteorin, visar vår forskning att studenterna arbetar med uppgifterna på ett helt annat sätt än tidigare. Det visar sig inte längre vara omöjligt att tillämpa Laplacetransformen redan under första året på civilingenjörsutbildning inom elektroteknik.

    Ursprungliga syftet med avhandlingen var att visa

    • hur studenter arbetar med laborationsuppgifter, speciellt i relation till målet att länka samman teori och verklighet
    • hur man kan förändra studenternas aktivitet, och därmed studenternas lärande, genom att förändra laborationsinstruktionen på ett systematiskt sätt.

    Under våren 2002 videofilmades studenter som utförde laborationer i en kurs i elkretsteori. Deras aktivitet analyserades. Speciellt studerades vilka frågor studenterna ställde till lärarna, på vilket sätt dessa frågor besvarades, och på vilket sätt svaren användes i den fortsatta aktiviteten.

    Detta ledde fram till en modell för lärande av sammansatta begrepp, som kunde användas både för att analysera vad studenterna gör och vad lärarna förväntar sig att studenterna ska lära sig. Med hjälp av modellen blev det då möjligt att se vad som behövde ändra i instruktionerna för att studenterna lättare skulle kunna utföra de aktiviteter som krävs för att länka teori och verklighet.

    Syftet med avhandlingen är därmed att

    ta fram en modell för lärande av ett sammansatt begrepp

    • visa hur denna modell kan användas för såväl analys av önskat lärandeobjekt, som av studenternas aktivitet under laborationer, och därmed det upplevda lärandeobjektet
    • använda modellen för att analysera vilka förändringar som är kritiska för  studenters lärande.

    Modellen användes för att förändra laborationsinstruktionerna. Lärarinterventionerna inkluderades i instruktionerna på ett systematiskt sätt utifrån dels vilka frågor som ställdes av studenterna, dels vilka frågor studenterna inte noterade, men som lärarna velat att studenterna skulle använda för att skapa relationer framför allt mellan teoretiska aspekter och mätresultat. Dessutom integrerades räkneövningar och laborationer.

    Videoinspelningar utfördes även våren 2003, då de nya instruktionerna användes. Även dessa analyserades med avseende på studenternas aktiviteter. Skillnader mellan resultaten från 2002 och 2003 står i fokus.

    Avhandlingens resultatdel består av:

    • Analys av studenternas frågor och lärarnas svar under labkursen 2002
    • Analys av de länkar studenterna behöver skapa för att lära
    • Analys av laborationsinstruktionerna före och efter förändringarna
    • Analys av den laborationsaktivitet som blev resultatet av de nya instruktionerna, och vilket lärande som då blev möjligt

    Avhandlingen avlutas med en diskussion om de slutsatser som kan dras angående möjligheter att via forskning utveckla modeller av undervisningssekvenser för lärande där målet är att länka samman teori och verklighet

  • 169.
    Carstensen, Anna-Karin
    et al.
    School of Engineering, Jönköping University, Jönköping, Sweden.
    Bernhard, Jonte
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Design science research: a powerful tool for improving methods in engineering education research2019Ingår i: European Journal of Engineering Education, ISSN 0304-3797, E-ISSN 1469-5898, Vol. 44, nr 1-2, s. 85-102Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Modelling is a central activity in practical engineering and something that is also useful in engineering education research (EER). Additionally, qualitative research methods have found important applications in engineering research, although their use in EER has not always been widely accepted. Design science research is a qualitative research approach in which the object of study is the design process, i.e. it simultaneously generates knowledge about the method used to design an artefact and the design or the artefact itself. This paper uses techniques from design science research to analyse the method used when deriving the learning of a complex concept(LCC) model, which we developed while designing teaching sequences for a course on electrical engineering. Our results demonstrate the value of design science research in EER and suggest that the LCC model is generally applicable in this field.

  • 170.
    Carstensen, Anna-Karin
    et al.
    Tekniska högskolan, Högskolan i Jönköping, Sweden.
    Bernhard, Jonte
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Design Science Research: an engineering research approach to improve methods for engineering education research2015Ingår i: Proceedings of 6th Research in Engineering Education Symposium (REES 2015): Translating Research into Practice, 2015, s. 653-661Konferensbidrag (Refereegranskat)
    Abstract [en]

    Modelling is an engineering activity commonly used by engineers, and can be used also in engineering education research (EER). The use of qualitative research methods have in EER not always been widely accepted but have recently gained more attention (Case & Light, 2011). There are, however, also qualitative research methods in engineering research that may be used in EER (Bernhard, in press). One such approach is design science research, where the object of research is the design process, i.e. the knowledge retrieved is not always knowledge about the phenomenon, the artefact, the design, but rather knowledge about the method used.

    This paper aims at researching the method used when deriving the model “the learning of a complex concept”, the LCC-model, which we developed while designing teaching sequences in a course in electrical engineering.

  • 171.
    Carstensen, Anna-Karin
    et al.
    Jönköping School of Engineering, Jönköping University, Sweden.
    Bernhard, Jonte
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Design Science Research as an Approach for Engineering Education Research2016Ingår i: The 12th International CDIO Conference / [ed] Jerker Björkqvist, Kristina Edström, Ronald J. Hugo, Juha Kontio, Janne Roslöf, Rick Sellens & Seppo Virtanen, Åbo: Turku University of Applied Sciences , 2016, s. 1072-1081Konferensbidrag (Refereegranskat)
    Abstract [en]

    Design Science Research is a research approach that is widely used in information systems, IS, but also in other areas where the development of an artefact is parallel to the development of a theory or methodology for this development. In our research we have developed the model “the learning of a complex concept”, LCC, as a method to analyze learning outcomes, as well intended as experienced by students.

    In this paper we will show how this model was developed, and how design science research was used to develop a methodology that may now be used in the iterative design and analysis of learning outcomes. LCC was developed while designing teaching sequences in a course in electrical engineering. The model was derived as a means to analyse videorecordings of students’ actions, during lab-sessions in an electric circuit course in the first year of an electrical engineering program.

    The model has contributed to the understanding of learning but also to the design of learning materials, and design science research has improved the methodology. Can this become an especially appropriate methodology for analysis of CDIO-projects? What may be learned, and what is actually learned in a CDIO-project? How can “the learning of a complex concept” (LCC) be used in the iterative design process designing a CDIO-project?

  • 172.
    Carstensen, Anna-Karin
    et al.
    Ingenjörshögskolan, Jönköping.
    Bernhard, Jonte
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Interactive lectures - linking theory to practice: Helping students pass the threshold when learning two-terminal equivalents in electrical engineering education2014Konferensbidrag (Refereegranskat)
  • 173.
    Carstensen, Anna-Karin
    et al.
    Högskolan i Jönköping.
    Bernhard, Jonte
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Make links: overcoming the threshold and entering the portal of understanding2016Ingår i: Threshold concepts in practice / [ed] Ray Land, Jan H. F. Meyer, Michael T. Flanagan, Rotterdam: Sense Publishers, 2016, s. 211-222Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    In engineering the student is often ‘faced with contrasting representations or models’ (Entwistle et al., 2005, p. 9), which Entwistle explores as ‘ways of thinking and practising’ (ibid). These contrasting representations are in electric circuits for example: graphs, mathematical models, drawings of circuits and the real circuits. In our research we have found that exploring the relationships – links – between these different representations, as well in the theory/model domain as in the object/event domain (Tiberghien, Vince, & Gaidioz, 2009) is of uttermost importance. We have developed a tool for investigation of ‘the learning of a complex concept’ (Carstensen & Bernhard, 2008a) which we have used in order to find critical aspects, which we call “key concepts” (Carstensen & Bernhard, 2008b), which open up the portal of understanding threshold concepts.

    In this paper we will explore these links further. As we have continued our work on how students make links between the different islands of single concepts, in order to make a whole of the complex concept, we have noted that the links between these islands are of different kinds. We will here discuss what kinds of relationships these links consist of, and how they differ in ways of coping with them for students, and how the teachers may notice and highlight these relationships in their instructions.

    We have video recorded students interactions during lab-work and analysed these tapes according to the Theory of Variation (Marton & Tsui, 2004). Now we are taking this further, and make a more detailed analysis of what the links are, and by that we contribute to the understanding of the nature of a threshold concept.

  • 174.
    Carstensen, Anna-Karin
    et al.
    Ingenjörshögskolan, Jönköping, Sweden.
    Bernhard, Jonte
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Make links: Overcoming the Threshold and Entering the Portal of Understanding2012Konferensbidrag (Övrigt vetenskapligt)
  • 175.
    Carstensen, Anna-Karin
    et al.
    Ingenjörshögskolan, Jönköping.
    Bernhard, Jonte
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Student learning in an electric circuit theory course: Critical aspects and task design2009Ingår i: European Journal of Engineering Education, ISSN 0304-3797, E-ISSN 1469-5898, Vol. 34, nr 4, s. 389-404Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Understanding time-dependent responses, such as transients, is important in electric circuit theory and other branches of engineering. However, transient response is considered difficult to learn since familiarity with advanced mathematical tools such as Laplace transforms is required. Here, we analyse and describe a novel learning environment design, the problem-solving lab, for learning transient response. This design merges problem-solving classes and labs, allowing students to engage in deep learning through the integrated use of tools like paper and pencil,MATLAB®, simulations, and experiments.Akey element in this design is the systematic use of variation in line with variation theory.We describe critical features for learning transient response, and ways to facilitate the establishment of links between the ‘worlds’ of theories/models and objects/events for students.We contend that an integrated use of tools, and systematic use of variation, is crucial for learning and establishing these links.

  • 176.
    Carstensen, Anna-Karin
    et al.
    Ingenjörshögskolan, Jönköping.
    Bernhard, Jonte
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    To learn a complex concept is to keep more than one concept in focal awareness simultaneously: an example from electrical engineering2013Konferensbidrag (Refereegranskat)
  • 177.
    Castro Meira, M. V.
    et al.
    University of Federal Reconcavo Bahia, Brazil University of Federal Bahia, Brazil .
    Ferreira da Silva, A.
    University of Federal Bahia, Brazil .
    Baldissera, G.
    Royal Institute Technology, Sweden .
    Persson, C.
    Royal Institute Technology, Sweden University of Oslo, Norway .
    Freitas, J. A.
    USN, USA .
    Gutman, N.
    Hebrew University of Jerusalem, Israel Hebrew University of Jerusalem, Israel .
    Saar, A.
    Hebrew University of Jerusalem, Israel Hebrew University of Jerusalem, Israel .
    Nur, Omer
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Optical characterization of ZnO nanopillars on Si and macroporous periodic Si structure2012Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 111, nr 12, s. 123527-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    ZnO nanopillars were successfully grown using both the vapor-liquid-solid and the aqueous chemical growth methods on different substrates, such as quartz, n-, and p-type non-porous Si wafer (flat) and microporous periodic Si structure (MPSiS). Scanning electron microscopy was employed to compare sample morphologies. The absorption was calculated employing the GW(0) method, based on the local density approximation, and with the projector augmented wave approach. Experiment and theory show a reasonable agreement when the shape of the optical absorption is considered. The measured absorption of ZnO nanopillars, on different substrates, is lower than that observed for ZnO films on quartz substrate, in the energy gap spectral range. A strong effect of MPSiS substrates on ZnO nanopillar properties is observed. The photoluminescence technique was also employed as an optical characterization.

  • 178.
    Chaharsoughi, Mina Shiran
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Tordera, Daniel
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Grimoldi, Andrea
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Engquist, Isak
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Fabiano, Simone
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Jonsson, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Hybrid Plasmonic and Pyroelectric Harvesting of Light Fluctuations2018Ingår i: Advanced Optical Materials, ISSN 2162-7568, E-ISSN 2195-1071Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    State-of-the-art solar energy harvesting systems based on photovoltaic technology require constant illumination for optimal operation. However, weather conditions and solar illumination tend to fluctuate. Here, a device is presented that extracts electrical energy from such light fluctuations. The concept combines light-induced heating of gold nanodisks (acting as plasmonic optical nanoantennas), and an organic pyroelectric copolymer film (poly(vinylidenefluoride-co-trifluoroethylene)), that converts temperature changes into electrical signals. This hybrid device can repeatedly generate current pulses, not only upon the onset of illumination, but also when illumination is blocked. Detailed characterization highlights the key role of the polarization state of the copolymer, while the copolymer thickness has minor influence on performance. The results are fully consistent with plasmon-assisted pyroelectric effects, as corroborated by combined optical and thermal simulations that match the experimental results. Owing to the tunability of plasmonic resonances, the presented concept is compatible with harvesting near infrared light while concurrently maintaining visible transparency.

  • 179.
    Chalangar, Ebrahim
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten. Halmstad Univ, Sweden.
    Machhadani, Houssaine
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Lim, Seung-Hyuk
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Karlsson, Fredrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Nur, Omer
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Pettersson, Håkan
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten. Halmstad Univ, Sweden; Lund Univ, Sweden; Lund Univ, Sweden.
    Influence of morphology on electrical and optical properties of graphene/Al-doped ZnO-nanorod composites2018Ingår i: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 29, nr 41, artikel-id 415201Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The development of future 3D-printed electronics relies on the access to highly conductive inexpensive materials that are printable at low temperatures (amp;lt;100 degrees C). The implementation of available materials for these applications are, however, still limited by issues related to cost and printing quality. Here, we report on the simple hydrothermal growth of novel nanocomposites that are well suited for conductive printing applications. The nanocomposites comprise highly Al-doped ZnO nanorods grown on graphene nanoplatelets (GNPs). The ZnO nanorods play the two major roles of (i) preventing GNPs from agglomerating and (ii) promoting electrical conduction paths between the graphene platelets. The effect of two different ZnO-nanorod morphologies with varying Al-doping concentration on the nanocomposite conductivity and the graphene dispersity are investigated. Time-dependent absorption, photoluminescence and photoconductivity measurements show that growth in high pH solutions promotes a better graphene dispersity, higher doping levels and enhanced bonding between the graphene and the ZnO nanorods. Growth in low pH solutions yields samples characterized by a higher conductivity and a reduced number of surface defects. These samples also exhibit a large persistent photoconductivity attributed to an effective charge separation and transfer from the nanorods to the graphene platelets. Our findings can be used to tailor the conductivity of novel printable composites, or for fabrication of large volumes of inexpensive porous conjugated graphene-semiconductor composites.

  • 180.
    Che, Canyan
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska fakulteten.
    Vagin, Mikhail
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska fakulteten.
    Wijeratne, Kosala
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Zhao, Dan
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Warczak, Magdalena
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Jonsson, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Crispin, Xavier
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Conducting Polymer Electrocatalysts for Proton-Coupled Electron Transfer Reactions: Toward Organic Fuel Cells with Forest Fuels2018Ingår i: Advanced Sustainable Systems, ISSN 2366-7486, Vol. 317Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Lignin is one of the most abundant biopolymers, constituting 25% of plants. The pulp and paper industries extract lignin in their process and today seek new applications for this by-product. Here, it is reported that the aromatic alcohols obtained from lignin depolymerization can be used as fuel in high power density electrical power sources. This study shows that the conducting polymer poly(3,4-ethylenedioxythiophene), fabricated from abundant ele-ments via low temperature synthesis, enables efficient, direct, and reversible chemical-to-electrical energy conversion of aromatic alcohols such as lignin residues in aqueous media. A material operation principle related to the rela-tively high molecular diffusion and ionic conductivity within the conducting polymer matrix, ensuring efficient uptake of protons in the course of proton-coupled electron transfers between organic molecules is proposed.

  • 181.
    Cherian, Dennis
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Armgarth, Astrid
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Beni, Valerio
    Res Inst Sweden, Sweden.
    Linderhed, Ulrika
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten. Res Inst Sweden, Sweden.
    Tybrandt, Klas
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Nilsson, David
    Res Inst Sweden, Sweden.
    Simon, Daniel
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Large-area printed organic electronic ion pumps2019Ingår i: FLEXIBLE AND PRINTED ELECTRONICS, ISSN 2058-8585, Vol. 4, nr 2, artikel-id 022001Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Biological systems use a large variety of ions and molecules of different sizes for signaling. Precise electronic regulation of biological systems therefore requires an interface which translates the electronic signals into chemically specific biological signals. One technology for this purpose that has been developed during the last decade is the organic electronic ion pump (OEIP). To date, OEIPs have been fabricated by micropatterning and labor-intensive manual techniques, hindering the potential application areas of this promising technology. Here we show, for the first time, fully screen-printed OEIPs. We demonstrate a large-area printed design with manufacturing yield amp;gt;90%. Screen-printed cation- and anion-exchange membranes are both demonstrated with promising ion selectivity and performance, with transport verified for both small ions (Na+,K+,Cl-) and biologically-relevant molecules (the cationic neurotransmitter acetylcholine, and the anionic anti-inflammatory salicylic acid). These advances open the iontronics toolbox to the world of printed electronics, paving the way for a broader arena for applications.

  • 182.
    Chey, Chan Oeurn
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Synthesis of ZnO and transition metals doped ZnO nanostructures, their characterization and sensing applications2014Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Nanotechnology is a technology of the design and the applications of nanoscale materials with their fundamentally new properties and functions. Nanosensor devices based on nanomaterials provide very fast response, low-cost, long-life time, easy to use for unskilled users, and provide high-efficiency.

    1-D ZnO nanostructures materials have great potential applications in various sensing applications. ZnO is a wide band gap (3.37 eV at room temperature) semiconductor materials having large exciton binding energy (60 meV) and excellent chemical stability, electrical, optical, piezoelectric and pyroelectric properties. By doping the transition metals (TM) into ZnO matrix, the properties of ZnO nanostructures can be tuned and its room  temperature ferromagnetic behavior can be enhanced, which provide the TM-doped ZnO nanostructures as promising candidate for optoelectronic, spintronics and high performance sensors based devices. The synthesis of ZnO and TM-doped ZnO nanostructures via the low temperature hydrothermal method is considered a promising technique due to low cost, environmental friendly, simple solution process, diverse 1-D ZnO nanostructures can be achieved, and large scale production on any type of substrate, and their properties can be controlled by the growth parameters. However, to synthesize 1-D ZnO and TM-doped ZnO nanostructures with controlled shape, structure and uniform size distribution on large area substrates with desirable properties, low cost and simple processes are of high interest and it is a big challenge at present.

    The main purpose of this dissertation aims to develop new techniques to synthesize 1-D ZnO and (Fe, Mn)-doped ZnO nanostructures via the hydrothermal method, to characterize and to enhance their functional properties for developing sensing devices such as biosensors for clinical diagnoses and environmental monitoring applications, piezoresistive sensors and UV photodetector.

    The first part of the dissertation deals with the hydrothermal synthesis of ZnO nanostructures with controlled shape, structure and uniform size distribution under different conditions and their structural characterization. The possible parameters affecting the growth which can alter the morphology, uniformity and properties of the ZnO nanostructures were investigated. Well-aligned ZnO nanorods have been fabricated for high sensitive piezoresistive sensor. The development of creatinine biosensor for clinical diagnoses purpose and the development of glucose biosensor for indirect determination of mercury ions for an inexpensive and unskilled users for environmental monitoring applications with highly sensitive, selective, stable, reproducible, interference resistant, and fast response time have been fabricated based on ZnO nanorods.

    The second part of the dissertation presents a new hydrothermal synthesis of (Fe, Mn)-doped-ZnO nanostructures under different preparation conditions, their properties characterization and the fabrication of piezoresistive sensors and UV photodetectors based devices were demonstrated. The solution preparation condition and growth parameters that influences on the morphology, structures and properties of the nanostructures were investigated. The fabrication of Mn-doped-ZnO NRs/PEDOT:PSS Schottky diodes used as high performance piezoresistive sensor and UV photodetector have been studied and Fe-doped ZnO NRs/FTO Schottky diode has also been fabricated for high performance of UV photodetector. Finally, a brief outlook into future challenges and relating new opportunities are presented in the last part of the dissertation.

    Delarbeten
    1. Fast synthesis, morphology transformation, structural and optical properties of ZnO nanorods grown by seed-free hydrothermal method
    Öppna denna publikation i ny flik eller fönster >>Fast synthesis, morphology transformation, structural and optical properties of ZnO nanorods grown by seed-free hydrothermal method
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    2014 (Engelska)Ingår i: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 211, nr 11, s. 2611-2615Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    A fast and low cost seed-free hydrothermal synthesis method to synthesize zinc oxide (ZnO) nanorods with controllable morphology, size and structure has been developed. Ammonia is used to react with water to tailor the ammonium hydroxide concentration, which provides a continuous source of OH− for hydrolysis and precipitation of the final products. Hence, allowing ZnO nanorods to growth on large areas of metal (Au and Ag coated glass), p-type Si and organic flexible (PEDOT: PSS) substrates. Increasing the growth time, the morphology transforms from pencil-like to hexagonal shape rod-like morphology. Within one hour the length of the ZnO nanorods has reached almost 1 µm. The optical characteristics has shown that the grown ZnO nanorods are dominated by two emission peaks, one is in the UV range centered at 381 nm and other one with relatively high intensity appears in the visible range and centered at 630 nm. While the growth duration was increased from 2 h to 6 h, the optical band gap was observed to increase from 2.8 eV to 3.24 eV, respectively. This fast and low cost method is suitable for LEDs, UV-photodetector, sensing, photocatalytic, multifunctional devices and other optoelectronic devices, which can be fabricated on any substrates, including flexible and foldable substrates.

    Nyckelord
    hydrothermal method, low temperature growth, seed-free growth ZnO, ZnO nanorods
    Nationell ämneskategori
    Elektroteknik och elektronik
    Identifikatorer
    urn:nbn:se:liu:diva-112903 (URN)10.1002/pssa.201431311 (DOI)000344461800029 ()
    Tillgänglig från: 2014-12-19 Skapad: 2014-12-19 Senast uppdaterad: 2017-12-05Bibliografiskt granskad
    2. ZnO nanorods based piezoresistive sensor synthesized by rapid mixing hydrothermal method
    Öppna denna publikation i ny flik eller fönster >>ZnO nanorods based piezoresistive sensor synthesized by rapid mixing hydrothermal method
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    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    We have successfully synthesized well-aligned, shape controlled and uniform size distribution of ZnO nanorods by using a rapid mixing hydrothermal method. The scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) characterizations showed that the ZnO nanorods grow along the c-axis with hexagonal wurtzite ZnO structure. The room temperature cathodoluminescence (CL) investigation revealed that the ZnO nanorods have optical emissions in both the UV and visible ranges and the crystal quality of the ZnO nanorods can be improved by increasing the growth duration. The well-aligned and uniform ZnO nanorods were used to fabricate efficient piezoresistive sensor. The piezoresistive sensor has demonstrated a pressure sensitivity of 0.033 KPa-1 with a fast response and recovery times within 0.088 and 0.29 s, respectively. The piezoresistive sensor has potential applications in industrial, civil and transportation fields. Furthermore, the fabricated sensor can be utilized as a very useful human-friendly interactive electronic device for load sensing.

    Nyckelord
    Growth ZnO nanorods, rapid mixing hydrothermal method, piezoresistive sensor
    Nationell ämneskategori
    Elektroteknik och elektronik
    Identifikatorer
    urn:nbn:se:liu:diva-112905 (URN)
    Tillgänglig från: 2014-12-19 Skapad: 2014-12-19 Senast uppdaterad: 2015-01-13
    3. Potentiometric creatinine biosensor based on ZnO nanowires
    Öppna denna publikation i ny flik eller fönster >>Potentiometric creatinine biosensor based on ZnO nanowires
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    2012 (Engelska)Ingår i: Journal of Nanoscience Letters, ISSN 2231-4008, Vol. 2, nr 4, s. 24-24Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    In the present work, we have grown well-aligned zinc oxide (ZnO) nanowires (NWs) on the surface of gold coated glass substrates by a low temperature aqueous chemical growth (ACG) approach and utilized it as a potentiometric creatinine biosensor. This was achieved by electrostatic immobilization of creatinine deiminase (CD) on the surface of the ZnO NWs followed by applying a chitosan membrane in conjunction with glutaraldehyde. This immobilization resulted in a sensitive, selective, stable, reproducible and fast creatinine biosensor. The potentiometric response of the ZnO sensor vs. Ag/AgCl reference electrode was found to be linear over a wide logarithmic concentration of creatinine electrolyte solution ranging from 1-1000 µM. The sensor illustrates good linear sensitivity slope curve of ~33.9 mV/decade along with a rapid response time of ~7 s. Furthermore, the sensor response was unaffected by normal concentrations of common interferences such as potassium, calcium, magnesium, sodium, copper ions and glucose.

    Ort, förlag, år, upplaga, sidor
    Cognizure, 2012
    Nyckelord
    ZnO nanowires; Potentiometric nanosensor; Electrochemical nanodevices; Creatinine deiminase; Creatinine
    Nationell ämneskategori
    Elektroteknik och elektronik
    Identifikatorer
    urn:nbn:se:liu:diva-112909 (URN)
    Tillgänglig från: 2014-12-19 Skapad: 2014-12-19 Senast uppdaterad: 2015-01-13Bibliografiskt granskad
    4. Indirect Determination of Mercury Ion by Inhibition of a Glucose Biosensor Based on ZnO Nanorods
    Öppna denna publikation i ny flik eller fönster >>Indirect Determination of Mercury Ion by Inhibition of a Glucose Biosensor Based on ZnO Nanorods
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    2012 (Engelska)Ingår i: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 12, nr 11, s. 15063-15077Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    A potentiometric glucose biosensor based on immobilization of glucose oxidase (GOD) on ZnO nanorods (ZnO-NRs) has been developed for the indirect determination of environmental mercury ions. The ZnO-NRs were grown on a gold coated glass substrate by using the low temperature aqueous chemical growth (ACG) approach. Glucose oxidase in conjunction with a chitosan membrane and a glutaraldehyde (GA) were immobilized on the surface of the ZnO-NRs using a simple physical adsorption method and then used as a potentiometric working electrode. The potential response of the biosensor between the working electrode and an Ag/AgCl reference electrode was measured in a 1mM phosphate buffer solution (PBS). The detection limit of the mercury ion sensor was found to be 0.5 nM. The experimental results provide two linear ranges of the inhibition from 0.5 x 10(-6) mM to 0.5 x 10(-4) mM, and from 0.5 x 10(-4) mM to 20 mM of mercury ion for fixed 1 mM of glucose concentration in the solution. The linear range of the inhibition from 10(-3) mM to 6 mM of mercury ion was also acquired for a fixed 10 mM of glucose concentration. The working electrode can be reactivated by more than 70% after inhibition by simply dipping the used electrode in a 10 mM PBS solution for 7 min. The electrodes retained their original enzyme activity by about 90% for more than three weeks. The response to mercury ions was highly sensitive, selective, stable, reproducible, and interference resistant, and exhibits a fast response time. The developed glucose biosensor has a great potential for detection of mercury with several advantages such as being inexpensive, requiring minimum hardware and being suitable for unskilled users.

    Ort, förlag, år, upplaga, sidor
    MDPI, 2012
    Nyckelord
    potentiometric inhibition biosensor, mercury, glucose oxidase, ZnO nanorods
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-86654 (URN)10.3390/s121115063 (DOI)000311429500043 ()
    Tillgänglig från: 2012-12-20 Skapad: 2012-12-20 Senast uppdaterad: 2017-12-06
    5. Low temperature aqueous chemical growth, structural, and optical properties of Mn-doped ZnO nanowires
    Öppna denna publikation i ny flik eller fönster >>Low temperature aqueous chemical growth, structural, and optical properties of Mn-doped ZnO nanowires
    2013 (Engelska)Ingår i: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 375, s. 125-130Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Mn-doped ZnO nanowires were successfully synthesized by using the low temperature aqueous chemical growth (ACG) method. Field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD), X-Ray photoelectron spectroscopy (XPS), and photoluminescence (PL) spectroscopy have been used to characterize the grown Zn1-xMnxO. The FESEM and the XRD measurements revealed that the grown of Mn-doped ZnO had wurtzite structure and the lattice parameters and the size of the crystal changed according to the change of concentration of the dopant. The chemical composition and charge states of the Mn ions doped in the ZnO nanowires was analyzed by the EDX and the XPS, respectively, indicated that the Mn ions is incorporated onto zinc sites in the ZnO nanowires. PL spectroscoCpy shows a strong ultraviolet (UV) emission peak at 378 nm (3.27 eV) from the Mn-doped ZnO nanowires, which is shifted 6 nm to the lower wavelength compared to ZnO nanowires grown by the same ACG method. The unique feature of our samples were the simple low temperature growth method which provides no clustering and the as-synthesized Mn-doped ZnO nanowires have shown good crystal quality. This capability to fabricate Mn-doped ZnO nanowires is of potential to develop new spintronic, photonic and sensor devices fabrication on any substrates.

    Ort, förlag, år, upplaga, sidor
    Elsevier, 2013
    Nyckelord
    Growth zinc oxide nanostructures, Low temperature aqueous chemical growth method, Hydrothermal method, Mn-doped ZnO nanowires
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-95815 (URN)10.1016/j.jcrysgro.2013.04.015 (DOI)000320586000024 ()
    Tillgänglig från: 2013-07-26 Skapad: 2013-07-26 Senast uppdaterad: 2017-12-06
    6. Fast piezoresistive sensor and UV photodetector based on Mn-doped ZnO nanorods
    Öppna denna publikation i ny flik eller fönster >>Fast piezoresistive sensor and UV photodetector based on Mn-doped ZnO nanorods
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    2014 (Engelska)Ingår i: Physica Status Solidi. Rapid Research Letters, ISSN 1862-6254, E-ISSN 1862-6270, Vol. 9, nr 1, s. 87-91Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    A low cost hydrothermal synthesis method to synthesize Mn-doped ZnO nanorods (NRs) with controllable morphology and structure has been developed. Ammonia is used to tailor the ammonium hydroxide concentration, which provides a source of OH– for hydrolysis and precipitation during the growth instead of HMT. The morphological, chemical composition, structural, and electronic structure studies of the Mn-doped ZnO NRs show that the Mn-doped ZnO NRs have a hexagonal wurtzite ZnO structure along the c-axis and the Mn ions replace the Zn sites in the ZnO NRs matrix without any secondary phase of metallic manganese element and manganese oxides observed. The fabricated PEDOT:PSS/Zn0.85Mn0.15O Schottky diode based piezoresistive sensor and UV photodetector shows that the piezoresistive sensor has pressure sensitivity of 0.00617 kPa–1 for the pressure range from 1 kPa to 20 kP and 0.000180 kPa–1for the pressure range from 20 kPa to 320 kPa with relatively fast response time of 0.03 s and the UV photodetector has both relatively high responsivity and fast response time of 0.065 A/W and 2.75 s, respectively. The fabricated Schottky diode can be utilized as a very useful human-friendly interactive electronic device for mass/force sensor or UV photodetector in everyday living life. This developed device is very promising for small-size, low-cost and easy-to-customize application-specific requirements. (© 2014 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim)

    Ort, förlag, år, upplaga, sidor
    John Wiley & Sons, 2014
    Nyckelord
    ZnO nanorods, Mn doping, hydrothermal method, piezoresistive sensors, ultraviolet photodetectors, optical properties
    Nationell ämneskategori
    Elektroteknik och elektronik
    Identifikatorer
    urn:nbn:se:liu:diva-112912 (URN)10.1002/pssr.201409453 (DOI)000348763500015 ()
    Tillgänglig från: 2014-12-19 Skapad: 2014-12-19 Senast uppdaterad: 2017-12-05Bibliografiskt granskad
    7. Synthesis of Fe-Doped ZnO Nanorods by Rapid Mixing Hydrothermal Method and Its Application for High Performance UV Photodetector
    Öppna denna publikation i ny flik eller fönster >>Synthesis of Fe-Doped ZnO Nanorods by Rapid Mixing Hydrothermal Method and Its Application for High Performance UV Photodetector
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    2014 (Engelska)Ingår i: Journal of Nanomaterials, ISSN 1687-4110, E-ISSN 1687-4129, Vol. 2014, nr 524530, s. 1-9Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    We have successfully synthesized Fe-doped ZnO nanorods by a new and simple method in which the adopted approach is by using ammonia as a continuous source of OH for hydrolysis instead of hexamethylenetetramine (HMT). The energy dispersive X-ray (EDX) spectra revealed that the Fe peaks were presented in the grown Fe-doped ZnO nanorods samples and the X-ray photoelectron spectroscopy (XPS) results suggested that Fe3+ is incorporated into the ZnO lattice. Structural characterization indicated that the Fe-doped ZnO nanorods grow along the c-axis with a hexagonal wurtzite structure and have single crystalline nature without any secondary phases or clusters of FeO or Fe3O4 observed in the samples. The Fe-doped ZnO nanorods showed room temperature (300 K) ferromagnetic magnetization versus field (M-H) hysteresis and the magnetization increases from 2.5 μemu to 9.1 μemu for Zn0.99Fe0.01O and Zn0.95Fe0.05O, respectively. Moreover, the fabricated Au/Fe-doped ZnO Schottky diode based UV photodetector achieved 2.33 A/W of responsivity and 5 s of time response. Compared to other Au/ZnO nanorods Schottky devices, the presented responsivity is an improvement by a factor of 3.9.

    Ort, förlag, år, upplaga, sidor
    Hindawi Publishing Corporation, 2014
    Nationell ämneskategori
    Elektroteknik och elektronik
    Identifikatorer
    urn:nbn:se:liu:diva-112914 (URN)10.1155/2014/524530 (DOI)000345016000001 ()
    Tillgänglig från: 2014-12-19 Skapad: 2014-12-19 Senast uppdaterad: 2017-12-05
  • 183.
    Chey, Chan Oeurn
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Alnoor, Hatim
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Abbasi, Mazhar Ali
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Nur, Omer
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Fast synthesis, morphology transformation, structural and optical properties of ZnO nanorods grown by seed-free hydrothermal method2014Ingår i: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 211, nr 11, s. 2611-2615Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A fast and low cost seed-free hydrothermal synthesis method to synthesize zinc oxide (ZnO) nanorods with controllable morphology, size and structure has been developed. Ammonia is used to react with water to tailor the ammonium hydroxide concentration, which provides a continuous source of OH− for hydrolysis and precipitation of the final products. Hence, allowing ZnO nanorods to growth on large areas of metal (Au and Ag coated glass), p-type Si and organic flexible (PEDOT: PSS) substrates. Increasing the growth time, the morphology transforms from pencil-like to hexagonal shape rod-like morphology. Within one hour the length of the ZnO nanorods has reached almost 1 µm. The optical characteristics has shown that the grown ZnO nanorods are dominated by two emission peaks, one is in the UV range centered at 381 nm and other one with relatively high intensity appears in the visible range and centered at 630 nm. While the growth duration was increased from 2 h to 6 h, the optical band gap was observed to increase from 2.8 eV to 3.24 eV, respectively. This fast and low cost method is suitable for LEDs, UV-photodetector, sensing, photocatalytic, multifunctional devices and other optoelectronic devices, which can be fabricated on any substrates, including flexible and foldable substrates.

  • 184.
    Chey, Chan Oeurn
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Alnoor, Hatim
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Liu, Xianjie
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska högskolan.
    Abbasi, Mazhar Ali
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Nur, Omer
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    ZnO nanorods based piezoresistive sensor synthesized by rapid mixing hydrothermal methodManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    We have successfully synthesized well-aligned, shape controlled and uniform size distribution of ZnO nanorods by using a rapid mixing hydrothermal method. The scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) characterizations showed that the ZnO nanorods grow along the c-axis with hexagonal wurtzite ZnO structure. The room temperature cathodoluminescence (CL) investigation revealed that the ZnO nanorods have optical emissions in both the UV and visible ranges and the crystal quality of the ZnO nanorods can be improved by increasing the growth duration. The well-aligned and uniform ZnO nanorods were used to fabricate efficient piezoresistive sensor. The piezoresistive sensor has demonstrated a pressure sensitivity of 0.033 KPa-1 with a fast response and recovery times within 0.088 and 0.29 s, respectively. The piezoresistive sensor has potential applications in industrial, civil and transportation fields. Furthermore, the fabricated sensor can be utilized as a very useful human-friendly interactive electronic device for load sensing.

  • 185.
    Chey, Chan Oeurn
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Ibupoto, Zafar Hussain
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Khun, Kimleang
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Nur, Omer
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Indirect Determination of Mercury Ion by Inhibition of a Glucose Biosensor Based on ZnO Nanorods2012Ingår i: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 12, nr 11, s. 15063-15077Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A potentiometric glucose biosensor based on immobilization of glucose oxidase (GOD) on ZnO nanorods (ZnO-NRs) has been developed for the indirect determination of environmental mercury ions. The ZnO-NRs were grown on a gold coated glass substrate by using the low temperature aqueous chemical growth (ACG) approach. Glucose oxidase in conjunction with a chitosan membrane and a glutaraldehyde (GA) were immobilized on the surface of the ZnO-NRs using a simple physical adsorption method and then used as a potentiometric working electrode. The potential response of the biosensor between the working electrode and an Ag/AgCl reference electrode was measured in a 1mM phosphate buffer solution (PBS). The detection limit of the mercury ion sensor was found to be 0.5 nM. The experimental results provide two linear ranges of the inhibition from 0.5 x 10(-6) mM to 0.5 x 10(-4) mM, and from 0.5 x 10(-4) mM to 20 mM of mercury ion for fixed 1 mM of glucose concentration in the solution. The linear range of the inhibition from 10(-3) mM to 6 mM of mercury ion was also acquired for a fixed 10 mM of glucose concentration. The working electrode can be reactivated by more than 70% after inhibition by simply dipping the used electrode in a 10 mM PBS solution for 7 min. The electrodes retained their original enzyme activity by about 90% for more than three weeks. The response to mercury ions was highly sensitive, selective, stable, reproducible, and interference resistant, and exhibits a fast response time. The developed glucose biosensor has a great potential for detection of mercury with several advantages such as being inexpensive, requiring minimum hardware and being suitable for unskilled users.

  • 186.
    Chey, Chan Oeurn
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Liu, Xianjie
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska högskolan.
    Alnoor, Hatim
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Nur, Omer
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Fast piezoresistive sensor and UV photodetector based on Mn-doped ZnO nanorods2014Ingår i: Physica Status Solidi. Rapid Research Letters, ISSN 1862-6254, E-ISSN 1862-6270, Vol. 9, nr 1, s. 87-91Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A low cost hydrothermal synthesis method to synthesize Mn-doped ZnO nanorods (NRs) with controllable morphology and structure has been developed. Ammonia is used to tailor the ammonium hydroxide concentration, which provides a source of OH– for hydrolysis and precipitation during the growth instead of HMT. The morphological, chemical composition, structural, and electronic structure studies of the Mn-doped ZnO NRs show that the Mn-doped ZnO NRs have a hexagonal wurtzite ZnO structure along the c-axis and the Mn ions replace the Zn sites in the ZnO NRs matrix without any secondary phase of metallic manganese element and manganese oxides observed. The fabricated PEDOT:PSS/Zn0.85Mn0.15O Schottky diode based piezoresistive sensor and UV photodetector shows that the piezoresistive sensor has pressure sensitivity of 0.00617 kPa–1 for the pressure range from 1 kPa to 20 kP and 0.000180 kPa–1for the pressure range from 20 kPa to 320 kPa with relatively fast response time of 0.03 s and the UV photodetector has both relatively high responsivity and fast response time of 0.065 A/W and 2.75 s, respectively. The fabricated Schottky diode can be utilized as a very useful human-friendly interactive electronic device for mass/force sensor or UV photodetector in everyday living life. This developed device is very promising for small-size, low-cost and easy-to-customize application-specific requirements. (© 2014 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim)

  • 187.
    Chey, Chan Oeurn
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Masood, Ansar
    Department of Materials Science, Royal Institute of Technology, Stockholm, Sweden.
    Riazanova, A.
    Department of Materials Science, Royal Institute of Technology, Stockholm, Sweden.
    Liu, Xianjie
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska högskolan.
    Rao, K. V.
    Department of Materials Science, Royal Institute of Technology, Stockholm, Sweden.
    Nur, Omer
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Synthesis of Fe-Doped ZnO Nanorods by Rapid Mixing Hydrothermal Method and Its Application for High Performance UV Photodetector2014Ingår i: Journal of Nanomaterials, ISSN 1687-4110, E-ISSN 1687-4129, Vol. 2014, nr 524530, s. 1-9Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We have successfully synthesized Fe-doped ZnO nanorods by a new and simple method in which the adopted approach is by using ammonia as a continuous source of OH for hydrolysis instead of hexamethylenetetramine (HMT). The energy dispersive X-ray (EDX) spectra revealed that the Fe peaks were presented in the grown Fe-doped ZnO nanorods samples and the X-ray photoelectron spectroscopy (XPS) results suggested that Fe3+ is incorporated into the ZnO lattice. Structural characterization indicated that the Fe-doped ZnO nanorods grow along the c-axis with a hexagonal wurtzite structure and have single crystalline nature without any secondary phases or clusters of FeO or Fe3O4 observed in the samples. The Fe-doped ZnO nanorods showed room temperature (300 K) ferromagnetic magnetization versus field (M-H) hysteresis and the magnetization increases from 2.5 μemu to 9.1 μemu for Zn0.99Fe0.01O and Zn0.95Fe0.05O, respectively. Moreover, the fabricated Au/Fe-doped ZnO Schottky diode based UV photodetector achieved 2.33 A/W of responsivity and 5 s of time response. Compared to other Au/ZnO nanorods Schottky devices, the presented responsivity is an improvement by a factor of 3.9.

  • 188.
    Chey, Chan Oeurn
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Patra, Hirak K
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biosensorer och bioelektronik. Linköpings universitet, Tekniska högskolan.
    Tengdelius, Mattias
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska högskolan.
    Golabi, Mohsen
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biosensorer och bioelektronik. Linköpings universitet, Tekniska högskolan.
    Parlak, Onur
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biosensorer och bioelektronik. Linköpings universitet, Tekniska högskolan.
    Imani, Roghayeh
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biosensorer och bioelektronik. Linköpings universitet, Tekniska högskolan.
    Elhag, Sami A. I.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Yandi, Wetra
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Tiwari, Ashutosh
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biosensorer och bioelektronik. Linköpings universitet, Tekniska högskolan.
    Impact of nanotoxicology towards technologists to end users2013Ingår i: Advanced Materials Letters, ISSN 0976-3961, E-ISSN 0976-397X, Vol. 4, nr 8, s. 591-597Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The length scale for nanomaterial is small enough to be invisible and presume innocence for the initial avoidance of the toxicity issues. Again it was beyond the understanding of the time frame when nanotechnology just blooms that a length scale itself might be an important toxic parameter apart from its materialistic properties. We present this report to address the fundamental issues and questions related to the nanotoxicity issues from laboratory to the land of applications. We emphasize about the basic nanoscale materials that are regularly being used by the scientific community and the nanotechnology based materials that has already in the market or will come soon.

  • 189.
    Chey, Chan Oeurn
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Usman Ali, Syed M.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Ibupoto, Zafar H.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Khun, Kimleang
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Nur, Omer
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Potentiometric creatinine biosensor based on ZnO nanowires2012Ingår i: Journal of Nanoscience Letters, ISSN 2231-4008, Vol. 2, nr 4, s. 24-24Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the present work, we have grown well-aligned zinc oxide (ZnO) nanowires (NWs) on the surface of gold coated glass substrates by a low temperature aqueous chemical growth (ACG) approach and utilized it as a potentiometric creatinine biosensor. This was achieved by electrostatic immobilization of creatinine deiminase (CD) on the surface of the ZnO NWs followed by applying a chitosan membrane in conjunction with glutaraldehyde. This immobilization resulted in a sensitive, selective, stable, reproducible and fast creatinine biosensor. The potentiometric response of the ZnO sensor vs. Ag/AgCl reference electrode was found to be linear over a wide logarithmic concentration of creatinine electrolyte solution ranging from 1-1000 µM. The sensor illustrates good linear sensitivity slope curve of ~33.9 mV/decade along with a rapid response time of ~7 s. Furthermore, the sensor response was unaffected by normal concentrations of common interferences such as potassium, calcium, magnesium, sodium, copper ions and glucose.

  • 190.
    Choudhury, Imran
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Design of Variable Attenuators Using Different Kinds of PIN-Diodes2013Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Variable attenuators are important circuits that can be employed in many radio frequency (RF) applications, e.g., in automatic gain control (AGC) amplifiers, broadband gain-control blocks at RF frequencies or as broadband vector modulators. For any applications, low insertion phase shift and low power consumption are of interest. A way to implement variable attenuators is using the RF PIN diode. The PIN diode is characterized by a low doped (I = intrinsic) semiconductor region between p- (P) and n-type (N) semiconductor regions. Besides the variable attenuators, the PIN-diode is used in other RF circuits, such as RF switches, limiters and phase shifters. This project presents the design of variable attenuators at 7.5 GHz and 500 MHz frequency bandwidth for ultra-wideband (UWB) applications using two different PIN diodes. The variable attenuators have a topology based on 90° hybrid couplers. The design is performed using Advance Design Systems (ADS) from Agilent Technologies Inc. After presenting the PIN diode and its equivalent circuit, the theory of the 90° passive directional branch line coupler and the operation principle of the variable attenuators are presented. As the selection of the appropriate PIN diode is a critical step in the design, special attention is dedicated to this aspect. It follows the design of the variable attenuators with extensive descriptions of the simulations in ADS. Firstly, both series and shunt attenuators are presented. However, as these circuits normally offer narrow band variable attenuation, the 900 directional branch line coupler is used in the attenuator for broader band operation. At the end, a double hybrid coupler is found to eliminate the ripple in the high attenuation state of the single hybrid coupled attenuator. So the final topology of the variable attenuator is a double hybrid coupler variable attenuator- Moreover, in this project, different PIN diodes are investigated for variable attenuator applications. Different manufacture companies are currently providing different kinds of PIN diodes in terms of parameters and packages. Every type of PIN diodes are providing different sort of advantages to the designers. That is why it has become more difficult for the RF designers to choose the right device for the specified application. Beside the design of the variable attenuator using PIN diodes, some considerations in form of a guide line to the designers while they are using the PIN diode for designing the variable attenuator. In this work, the used PIN diodes are a beam lead PIN diode and chip PIN diode. The beam lead PIN diode is used because it is manufactured for high frequency and it produces excellent electrical performance and isolation at high frequencies. On the other hand, the chip PIN diode eliminates the problem of package parasitics. However, printed circuit board (PCB) manufacturing limitations at the university laboratory incline the balance in the favor of the beam lead PIN diode, HPND- 4005 from Avagotech, instead of the also considered chip diode MA-COM MA4P202.

  • 191.
    Cotrone, Serafina
    et al.
    Università di Bari “Aldo Moro”.
    Ambrico, Marianna
    CNR-IMIP.
    Toss, Henrik
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Angione, M. Daniela
    Università di Bari “Aldo Moro”.
    Magliulo, Maria
    Università di Bari “Aldo Moro”.
    Mallardi, Antonia
    CNR-IPCF.
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Palazzo, Gerardo
    Università di Bari “Aldo Moro”.
    Horowitz, Gilles
    University Paris Diderot.
    Ligonzo, Teresa
    Università di Bari “Aldo Moro”.
    Torsi, Luisa
    Università di Bari “Aldo Moro”.
    Phospholipid film in electrolyte-gated organic field-effect transistors2012Ingår i: Organic electronics, ISSN 1566-1199, E-ISSN 1878-5530, Vol. 13, nr 4, s. 638-644Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A totally innovative electrolyte-gated field effect transistor, embedding a phospholipid film at the interface between the organic semiconductor and the gating solution, is described. The electronic properties of OFETs including a phospholipid film are studied in both pure water and in an electrolyte solution and compared to those of an OFET with the organic semiconductor directly in contact with the gating solution. In addition, to investigate the role of the lipid layers in the charge polarization process and quantify the field-effect mobility, impedance spectroscopy was employed. The results indicate that the integration of the biological film minimizes the penetration of ions into the organic semiconductor thus leading to a capacitive operational mode as opposed to an electrochemical one. The OFETs operate at low voltages with a field-effect mobility in the 10−3 cm2 V−1 s−1 range and an on/off current ratio of 103. This achievement opens perspectives to the development of FET biosensors potentially capable to operate in direct contact with physiological fluids.

  • 192.
    Crispin, Xavier
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Carbon nanotubes get high2016Ingår i: NATURE ENERGY, ISSN 2058-7546, Vol. 1, artikel-id 16037Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    Waste heat can be converted to electricity by thermoelectric generators, but their development is hindered by the lack of cheap materials with good thermoelectric properties. Now, carbon-nanotube-based materials are shown to have improved properties when purified to contain only semiconducting species and then doped.

  • 193.
    Crispin, Xavier
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Herlogsson, Lars
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Larsson, Oscar
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Said, Elias
    Royal Institute of Technology, Stockholm, Sweden.
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Polyelectrolyte-Gated Organic Field-Effect Transistors2010Ingår i: Iontronics: Ionic Carriers in Organic Electronic Materials and Devices / [ed] Janell Leger, Magnus Berggren, Sue Carter, Boca Raton: CRC Press; Taylor & Francis Group , 2010, s. 193-218Kapitel i bok, del av antologi (Övrigt vetenskapligt)
    Abstract [en]

    The field of organic electronics promises exciting new technologies based on inexpensive and mechanically flexible electronic devices. It has progressed over the past three decades to the point of commercial viability and is projected to grow to a 30 billion dollar market by the year 2015. Exploring new applications and device architectures, this book sets the tone for that exploration, gathering a community of experts in this area who are focused on the use of ionic functions to define the principle of operation in polymer devices. The contributors detail relevant technologies based on organic electronics, including polymer electrochromic devices and light-emitting electrochemical cells.

  • 194.
    Crispin, Xavier
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Kalinin, Sergei V.
    Oak Ridge National Lab, TN 37831 USA.
    Semiconducting Polymers: Probing the solid-liquid interface2017Ingår i: Nature Materials, ISSN 1476-1122, E-ISSN 1476-4660, Vol. 16, nr 7, s. 704-705Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Exploring the minute mechanical deformations induced by electrical bias at the interface with electrolytes allows the identification of local crystallinity and distinguishing adsorption and intercalation of ions in electroactive polymers.

  • 195.
    Crispin, Xavier
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska högskolan.
    Marciniak, S.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska högskolan.
    Osikowicz, Wojciech
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska högskolan.
    Zotti, G.
    Instituto Consiglio Nazionale delle Ricerche per l' Energetica e le Interfasi, Padova, Italy.
    Denier Van Der Gon, A. W.
    Faculty of Applied Physics, Eindhoven University of Technology, Eindhoven, The Netherlands.
    Louwet, F.
    Chemistry Department, R&D Materials Research, Agfa Gevaert N.V., Mortsel, Belgium.
    Fahlman, Mats
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Groenendaal, L.
    Chemistry Department, R&D Materials Research, Agfa Gevaert N.V., Mortsel, Belgium.
    De Schryver, F.
    Afdeling Fotochemie en Spectroscopie, Katholieke Universiteit Leuven, Heverlee, Belgium.
    Salaneck, William R.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska högskolan.
    Conductivity, Morphology, Interfacial Chemistry, and Stability of Poly(3,4- ethylene dioxythiophene)–Poly(styrene sulfonate): A Photoelectron Spectroscopy Study2003Ingår i: Journal of Polymer Science Part B: Polymer Physics, ISSN 0887-6266, E-ISSN 1099-0488, Vol. 41, nr 21, s. 2561-2583Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    X-ray photoelectron spectroscopy (XPS) has been used to characterize poly(3,4-ethylene dioxythiophene)-poly(styrene sulfonate) (PEDT/PSS), one of the most common electrically conducting organic polymers. A correlation has been established between the composition, morphology, and polymerization mechanism, on the one hand, and the electric conductivity of PEDT/PSS, on the other hand. XPS has been used to identify interfacial reactions occurring at the polymer-on-ITO and polymer-on-glass interfaces, as well as chemical changes within the polymer blend induced by electrical stress and exposure to ultraviolet light.

  • 196.
    Cronborn, Jesper
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Automatization of test rig for microwave ovens2013Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The thesis work is a part of a project where the major goal is to improve the efficiency of the evaluations of microwave ovens at Whirlpool Sweden AB. The purpose of the work has been to develop an automatic control and measurement system for microwave ovens. In an earlier thesis work, a test rig has been developed and this test rig has been further developed to an autonomous system. The software for this system is developed in LabVIEW and interfaces to some measuring instruments has been implemented for the system. As a plan for the programming work, UML-diagrams were created in Visual Paradigm To make it easy for the user to handle the system, a user interface has been created in LabVIEW. The system handles different XML-files: oven profiles and test profiles, which are defined by the user. An oven profile contains coordinates for specific positions at the front of a microwave oven, e.g. button positions and corners. There will be one oven profile per oven model. A test profile contains different stages with position names, operations and time delays. The position names are the names of the positions defined in the oven profile. The results from a measurement will be saved in a CSV-file.

  • 197.
    Dahlström, Patrik
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Geo-based Mobility Control for Mobile Traffic Simulators2013Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Most mobile traffic simulators of today depend on the user to supply the mobility behavior of the simulated UEs. This becomes a problem when certain wanted mobility characteristics are to be tested, since the user have to go trough a trial-and-error procedure to come up with the proper mobility behavior. This thesis presents two approaches to mobility control, where the aim is to control UE mobility based on certain mobility characteristics supplied by the end user.

    The first approach introduces the concept of assigning tasks to UEs, e.g. “cross cell border” or “move to a certain cell”. Furthermore, concepts from control theory are borrowed to control the task assignment process, making it more dynamic and robust.

    The second approach iteratively calculate movement patterns for the UEs in an area until it finds a movement pattern that has a high probability of satisfying the user’s requested mobility characteristics.

    In order to properly evaluate these two approaches a prototype simulator was developed, as well as a virtual network controller to be tested. This test environment simulate a simplified tree network topology.

    Both approaches was tested to control the total number of handovers per second in a simulated area. They both show high accuracy and acceptable precision. Additionally, the task based approach was used to control the cell utilization in a target cell. However, the cell utilization tests showed a lower accuracy and precision than the handover rate control tests.

  • 198.
    Dahm, Rickard
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Autotuning of RPM controller2013Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Under detta projekt som utfördes på Scania CV AB undersöktes möjligheten att använda sig av en adaptiv regulator för att reglera motorvarvtalet på en lastbilsmotor som driver utrustning via ett kraftuttag. Fördelen med att använda sig av adaptiv reglering istället för den parameterstyrda PID reglering som används idag är att regulatorn kan klara av fler utrustningstyper. Dagens regulator kan få problem vid stora belastningsmoment eller tröghetsmoment. Detta kan lösas med adaptiv reglering.

    I rapporten presenteras en modellbaserad regulator som använder systemets tröghetsmoment. Då systemets tröghetsmoment är okänt ges även förslag på hur detta skulle kunna estimeras. Den modellbaserade regulatorn visar sig vara mycket effektiv då skattningen av tröghetsmomentet lyckas. Det Kalmanfilter som designats för att estimera systemet fungerar dock ej för alla önskvärda fall och en fortsatt studie på hur denna design ska se ut krävs innan regulatorn testas på ett verkligt system.

  • 199.
    David, Denis
    et al.
    Universidade Federal da Bahia, Campus Ondina, Salvador-Ba, Brazil.
    Alnoor, Hatim
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Mancir da Silva Santana, Victor
    Universidade Federal da Bahia, Campus Ondina, Salvador-Ba, Brazil.
    Bargiela, Pascal
    Royal Institute of Technology, Stockholm, Sweden.
    Nur, Omer
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Baldissera, Gustavo
    Royal Institute of Technology, Stockholm, Sweden.
    Persson, Clas
    Royal Institute of Technology, Stockholm, Sweden; University of Oslo, Oslo, Norway.
    Ferreira da Silva, Antonio
    Universidade Federal da Bahia, Campus Ondina, Salvador-Ba, Brazil.
    Optical properties from photoelectron energy-loss spectroscopy of low-temperature aqueous chemically synthesized ZnO nanorods grown on Si2019Ingår i: Semiconductor Science and Technology, ISSN 0268-1242, E-ISSN 1361-6641, Vol. 34, nr 4, artikel-id 045019Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The optical properties of zinc oxide (ZnO) nanorods (NRs) synthesized by the low-temperature aqueous chemical method on top of silicon (Si) substrate have been investigated by means of photoelectron energy loss spectroscopy (PEELS). The ZnO NRs were obtained by the low temperature aqueous chemical synthesis on top of Si substrate. The measured valence band, the dynamical dielectric functions and optical absorption of the material show a reasonable agreement when the trending and shape of the theoretical calculations are considered. A first-principle calculation based on density functional theory (DFT) was performed using the partially self-consistent GW approximation (scGW0) and compared to the experimental results. The application of these two techniques brings a new analysis of the electronic properties of this material. The experimental results regarding the density of states (DOS) obtained for the valence band using x-ray photoelectron spectroscopy (XPS) was found to be consistent with the theoretical calculated value. Due to this consistency, the same wavefunctions was then employed to calculate the dielectric function of the ZnO NRs. The experimentally extracted dielectric function was also consistent with the calculated values.

  • 200.
    del Pozo, Freddy G.
    et al.
    Institute Ciencia Mat Barcelona ICMAB CSIC, Spain; Networking Research Centre Bioengn Biomat and Nanomed CIBER, Spain.
    Fabiano, Simone
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Pfattner, Raphael
    Institute Ciencia Mat Barcelona ICMAB CSIC, Spain; Networking Research Centre Bioengn Biomat and Nanomed CIBER, Spain.
    Georgakopoulos, Stamatis
    Institute Ciencia Mat Barcelona ICMAB CSIC, Spain; Networking Research Centre Bioengn Biomat and Nanomed CIBER, Spain.
    Galindo, Sergi
    Institute Ciencia Mat Barcelona ICMAB CSIC, Spain; Networking Research Centre Bioengn Biomat and Nanomed CIBER, Spain.
    Liu, Xianjie
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska fakulteten.
    Braun, Slawomir
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska fakulteten.
    Fahlman, Mats
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska fakulteten.
    Veciana, Jaume
    Institute Ciencia Mat Barcelona ICMAB CSIC, Spain; Networking Research Centre Bioengn Biomat and Nanomed CIBER, Spain.
    Rovira, Concepcio
    Institute Ciencia Mat Barcelona ICMAB CSIC, Spain; Networking Research Centre Bioengn Biomat and Nanomed CIBER, Spain.
    Crispin, Xavier
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska fakulteten.
    Mas-Torrent, Marta
    Institute Ciencia Mat Barcelona ICMAB CSIC, Spain; Networking Research Centre Bioengn Biomat and Nanomed CIBER, Spain.
    Single Crystal-Like Performance in Solution-Coated Thin-Film Organic Field-Effect Transistors2016Ingår i: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 26, nr 14, s. 2379-2386Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In electronics, the field-effect transistor (FET) is a crucial cornerstone and successful integration of this semiconductor device into circuit applications requires stable and ideal electrical characteristics over a wide range of temperatures and environments. Solution processing, using printing or coating techniques, has been explored to manufacture organic field-effect transistors (OFET) on flexible carriers, enabling radically novel electronics applications. Ideal electrical characteristics, in organic materials, are typically only found in single crystals. Tiresome growth and manipulation of these hamper practical production of flexible OFETs circuits. To date, neither devices nor any circuits, based on solution-processed OFETs, has exhibited an ideal set of characteristics similar or better than todays FET technology based on amorphous silicon. Here, bar-assisted meniscus shearing of dibenzo-tetrathiafulvalene to coat-process self-organized crystalline organic semiconducting domains with high reproducibility is reported. Including these coatings as the channel in OFETs, electric field and temperature-independent charge carrier mobility and no bias stress effects are observed. Furthermore, record-high gain in OFET inverters and exceptional operational stability in both air and water are measured.

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