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  • 51.
    Andersson Ersman, Peter
    et al.
    Acreo AB, Norrköping, Sweden .
    Kawahara, Jun
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Printed passive matrix addressed electrochromic displays2013In: Organic electronics, ISSN 1566-1199, E-ISSN 1878-5530, Vol. 14, no 12, p. 3371-3378Article in journal (Refereed)
    Abstract [en]

    Flexible displays are attracting considerable attention as a visual interface for applications such as in electronic papers and paper electronics. Passive or active matrix-addressing of individual pixels require display elements that include proper signal addressability, which is typically provided by non-linear device characteristics or by incorporating transistors into each pixel, respectively. Including such additional devices into each pixel element make manufacturing of flexible displays using adequate printing techniques very hard or even impossible. Here, we report all-printed passive matrix-addressed electrochromic displays (PMAD) that can be manufactured using standard printing tools. Poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate) (PEDOT:PSS) serves as the conducting and electrochromic pixel electrodes and carbon paste is used as the pixel counter electrodes. These electrodes sandwich self-assembled layers of a polyelectrolyte that are confined to desired pixel areas via surface energy patterning. The particular choice of materials results in a desired current vs. voltage threshold that enables addressability in electronic cross-point matrices. The resulting PMAD, built up from a robust architecture including only few different materials, operates at less than 3 V, exhibits high color switch contrast without any cross-talk promises for high-volume and low-cost production of flexible displays using reel-to-reel printing tools on plastic foils and on paper.

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    suppl. info fig. 6e
  • 52.
    Andersson Ersman, Peter
    et al.
    Acreo AB, Sweden.
    Nilsson, David
    Acreo AB, Sweden.
    Kawahara, Jun
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology. Acreo AB, Sweden .
    Gustafsson, Göran
    Acreo AB, Sweden.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Fast-switching all-printed organic electrochemical transistors2013In: Organic electronics, ISSN 1566-1199, E-ISSN 1878-5530, Vol. 14, no 5, p. 1276-1280Article in journal (Refereed)
    Abstract [en]

    Symmetric and fast (∼5 ms) on-to-off and off-to-on drain current switching characteristics have been obtained in screen printed organic electrochemical transistors (OECTs) including PEDOT:PSS (poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonic acid)) as the active transistor channel material. Improvement of the drain current switching characteristics is made possible by including a carbon conductor layer on top of PEDOT:PSS at the drain electrode that is in direct contact with both the channel and the electrolyte of the OECT. This carbon conductor layer suppresses the effects from a reduction front that is generated in these PEDOT:PSS-based OECTs. In the off-state of these devices this reduction front slowly migrate laterally into the PEDOT:PSS drain electrode, which make off-to-on switching slow. The OECT including carbon electrodes was manufactured using only standard printing process steps and may pave the way for fully integrated organic electronic systems that operate at low voltages for applications such as logic circuits, sensors and active matrix addressed displays.

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  • 53.
    Andersson, Johan
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Schelander, Adam
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Design and verification of automotive power supply2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In the current and next generation automotive telematic platforms, high demands are put on high efficiency power supplies. This thesis investigates different switch mode power converter solutions that operates with high efficiency for both low and high power loads. A market survey was conducted alongside meetings with ACTIA Nordic and their subcontractors. Three solutions from the market survey were selected for further investigation. One solution from the investigation was selected and implemented as a demonstration platform for further testing. The result shows a full test sequence for the designed power supply solution.

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    Design and verification of automotive power supply
  • 54.
    Andrijauskas, T.
    et al.
    Vilnius State University.
    Shylau, Artsem
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Zozoulenko, Igor
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Thomas-Fermi and Poisson modeling of gate electrostatics in graphene nanoribbon2012In: Lithuanian Journal of Physics, ISSN 1648-8504, Vol. 52, no 1, p. 63-69Article in journal (Refereed)
    Abstract [en]

    We describe a simple graphene nanoribbon and bottom gate system and present numerical algorithms for solving Poissons and Thomas-Fermi equations for electrons in the graphene nanoribbon. The Poissons equation is solved using finite difference and finite element methods. Using the Poisson and Thomas-Fermi equations we calculate an electrostatic potential and surface electron density in the graphene nanoribbon. Finally, the Poisson-Thomas-Fermi model for the graphene nanoribbon is compared to a tight-binding Hartree model. The results show a good correspondence with the tight-binding model. The developed solver of the Poissons equation can be used in the future calculations of more complex graphene and gate systems.

  • 55.
    Anton, Gagner
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Hebib, Nino
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    FPGA Software Development for Control Purposes of High-Frequency Switching Power Converters2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    FPGA stands for Field Programmable Gate Array and it is a technology that has been on the rise the last decades. With a decrease in size of the logic elements commercially available products have started to have more built-in functionality in one package and by being reprogrammable makes the system a powerful competitor among its neighbors. FPGA technology in comparison with Digital Signal Processing technology is generally interesting because of the parallelism of the programming that can be made. This allows for more operations in less time. In this thesis a system is developed to control power converters with control signals in high frequency. A previous project is used as a base and a toolchain of new components are implemented to create a new, more generic system. The previous system is evaluated and a new protocol for communication is developed. The toolchain with the necessary control blocks is implemented in Quartus II that includes a timer block, a pulse width modulation block, a PID controller block and a FIR-filter block. The system is used to control a power converter and the result is evaluated.

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    FPGA Software Development for Control Purposes of High-Frequency Switching Power Converters
  • 56.
    Anwar, Nargis
    et al.
    Dundalk Inst Technol, Ireland.
    Armstrong, Gordon
    Univ Limerick, Ireland.
    Laffir, Fathima
    Univ Limerick, Ireland.
    Dickinson, Calum
    Univ Limerick, Ireland.
    Vagin, Mikhail
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering.
    McCormac, Timothy
    Dundalk Inst Technol, Ireland.
    Redox switching of polyoxometalate-doped polypyrrole films in ionic liquid media2018In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 265, p. 254-258Article in journal (Refereed)
    Abstract [en]

    The surface immobilization of the parent Dawson polyoxometalate (POM) as a counter-ion for the electropolymerization of polypyrrole (PPy) or as an electrode-adhered solid was utilized for voltammetric studies of the surface adhered POM in room temperature ionic liquids (RTIL). Illustrating the efficiency of intermediate stabilization, voltammetry at POM-modified electrodes in a PF6-based RTIL revealed richer redox behaviour and higher stabilization in comparison with aqueous electrolytes and with BF4-based RTIL, respectively. High stability of the POM-doped PPy towards continuous charge-discharge voltammetric redox cycles was confirmed by minor changes in film morphology observed after the cycling in RTILs. (c) 2017 Elsevier Ltd. All rights reserved.

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  • 57.
    Apaydin, Dogukan H.
    et al.
    Johannes Kepler University of Linz, Austria.
    Gora, Monika
    University of Warsaw, Poland.
    Portenkirchner, Engelbert
    University of Innsbruck, Austria.
    Oppelt, Kerstin T.
    Johannes Kepler University of Linz, Austria.
    Neugebauer, Helmut
    Johannes Kepler University of Linz, Austria.
    Jakesoya, Marie
    Johannes Kepler University of Linz, Austria.
    Glowacki, Eric D.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Kunze-Liebhaeuser, Julia
    University of Innsbruck, Austria.
    Zagorska, Malgorzata
    Warsaw University of Technology, Poland.
    Mieczkowski, Jozef
    University of Warsaw, Poland.
    Serdar Sariciftci, Niyazi
    Johannes Kepler University of Linz, Austria.
    Electrochemical Capture and Release of CO2 in Aqueous Electrolytes Using an Organic Semiconductor Electrode2017In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, no 15, p. 12919-12923Article in journal (Refereed)
    Abstract [en]

    Developing efficient methods for capture and controlled release of carbon dioxide is crucial to any carbon. capture and utilization technology. Herein we present an approach using an organic. semiconductor electrode to electrochemically capture dissolved CO2 in aqueous electrolytes. The process relies on electrochemical reduction of a thin film of a naphthalene bisimide derivative, 2,7,bis (4-(2- (2-ethylhexyl)thiazol-4-yl)phenyObenzo [lmn][3,8] phenanthroline-1,3,6,8(2H,7H)-tetraone (NBIT). This molecule is specifically tailored to afford one-electron reversible and one-electron quasi-reversible reduction in aqueous conditions while, not dissolving or degrading. The reduced NBIT reacts with CO2 to form a stable aemicarbonate salt, which can be subsequently oxidized electrochemically to release CO2. The semicarbonate structure is confirmed by in situ IR spectroelectrochemistry. This process of capturing and releasing carbon dioxide can be realized in an oxygen-free environment under ambient pressure and temperature, with uptake efficiency for CO2 capture of similar to 2.3 mmol g(-1). This is on par with the best solution-phase amine chemical capture technologies available today.

  • 58.
    Arain, Munazza
    et al.
    University of Sindh, Pakistan.
    Nafady, Ayman
    King Saud University, Saudi Arabia; Sohag University, Egypt.
    Sirajuddin,
    Univ Sindh, Pakistan.
    Ibupoto, ZH
    Univ Sindh, Pakistan.
    Sherazi, Syed Tufail Hussain
    University of Sindh, Pakistan.
    Shaikh, Tayyaba
    University of Sindh, Pakistan.
    Khan, Hamayun
    Islamia Coll University, Pakistan.
    Alsalme, Ali
    King Saud University, Saudi Arabia.
    Niaz, Abdul
    Bannu University of Science and Technology, Pakistan.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Simpler and highly sensitive enzyme-free sensing of urea via NiO nanostructures modified electrode2016In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 6, no 45, p. 39001-39006Article in journal (Refereed)
    Abstract [en]

    In this study, NiO nanostructures were synthesized via a hydrothermal process using ascorbic acid as doping agent in the presence of ammonia. As prepared nanostructures were characterized using Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Brunauer-Emmett-Teller (BET) specific surface area analysis, and thermogravimetric analysis (TGA). These analyses showed that these nanostructures are in the form of cotton-like porous material and crystalline in nature. Furthermore, the average size of these NiO crystallites was estimated to be 3.8 nm. These nanostructures were investigated for their potential to be a highly sensitive and selective enzyme-free sensor for detection of urea after immobilizing on a glassy carbon electrode (GCE) using 0.1% Nafion as binder. The response of this as developed amperometric sensor was linear in the range of 100-1100 mu M urea with a R-2 value of 0.990 and limit of detection (LOD) of 10 mu M. The sensor responded negligibly to various interfering species including glucose, uric acid, and ascorbic acid. This sensor was applied successfully for determining urea in real water samples such as mineral water, tap water, and river water with acceptable recovery.

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  • 59.
    Arbring Sjöström, Theresia
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Gabrielsson, Erik
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Janson, Per
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Poxson, David
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Seitanidou, Maria S.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Simon, Daniel
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    A Decade of Iontronic Delivery Devices2018In: Advanced Materials Technologies, ISSN 2365-709X, Vol. 3, no 5, article id 1700360Article, review/survey (Refereed)
    Abstract [en]

    In contrast to electronic systems, biology rarely uses electrons as the signal to regulate functions, but rather ions and molecules of varying size. Due to the unique combination of both electronic and ionic/molecular conductivity in conjugated polymers and polyelectrolytes, these materials have emerged as an excellent tool for translating signals between these two realms, hence the field of organic bioelectronics. Since organic bioelectronics relies on the electron-mediated transport and compensation of ions (or the ion-mediated transport and compensation of electrons), a great deal of effort has been devoted to the development of so-called "iontronic" components to effect precise substance delivery/transport, that is, components where ions are the dominant charge carrier and where ionic-electronic coupling defines device functionality. This effort has resulted in a range of technologies including ionic resistors, diodes, transistors, and basic logic circuits for the precisely controlled transport and delivery of biologically active chemicals. This Research News article presents a brief overview of some of these "ion pumping" technologies, how they have evolved over the last decade, and a discussion of applications in vitro, in vivo, and in plantae.

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  • 60.
    Arbring Sjöström, Theresia
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Jonsson, Amanda
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Gabrielsson, Erik
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Simon, Daniel
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Tybrandt, Klas
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Miniaturized Ionic Polarization Diodes for Neurotransmitter Release at Synaptic Speeds2019In: ADVANCED MATERIALS TECHNOLOGIES, ISSN 2365-709X, article id 1900750Article in journal (Refereed)
    Abstract [en]

    Current neural interfaces rely on electrical stimulation pulses to affect neural tissue. The development of a chemical delivery technology, which can stimulate neural tissue with the bodys own set of signaling molecules, would provide a new level of sophistication in neural interfaces. Such technology should ideally provide highly local chemical delivery points that operate at synaptic speed, something that is yet to be accomplished. Here, the development of a miniaturized ionic polarization diode that exhibits many of the desirable properties for a chemical neural interface technology is reported. The ionic diode shows proper diode rectification and the current switches from off to on in 50 mu s at physiologically relevant electrolyte concentrations. A device model is developed to explain the characteristics of the ionic diode in more detail. In combination with experimental data, the model predicts that the ionic polarization diode has a delivery delay of 5 ms to reach physiologically relevant neurotransmitter concentrations at subcellular spatial resolution. The model further predicts that delays of amp;lt;1 ms can be reached by further miniaturization of the diode geometry. Altogether, the results show that ionic polarization diodes are a promising building block for the next generation of chemical neural interfaces.

    The full text will be freely available from 2020-11-22 14:26
  • 61.
    Arbring Sjöström, Theresia
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Jonsson, Amanda
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering. Stanford University, CA 94305 USA.
    Gabrielsson, Erik
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Kergoat, Loig
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering. Aix Marseille University, France.
    Tybrandt, Klas
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Simon, Daniel
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Cross-Linked Polyelectrolyte for Improved Selectivity and Processability of lontronic Systems2017In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, no 36, p. 30247-30252Article in journal (Refereed)
    Abstract [en]

    On-demand local release of biomolecules enables fine-tuned stimulation for the next generation of neuromodulation therapies. Such chemical stimulation is achievable using iontronic devices based on microfabricated, highly selective ion exchange membranes (IEMs). Current limitations in processability and performance of thin film LEMs hamper future developments of this technology. Here we address this limitation by developing a cationic IEM with excellent processability and ionic selectivity: poly(4-styrenesulfonic acidco-maleic acid) (PSS-co-MA) cross-linked with polyethylene glycol (PEG). This enables new design opportunities and provides enhanced compatibility with in vitro cell studies. PSSA-co-MA/PEG is shown to out-perform the cation selectivity of the previously used iontronic material.

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  • 62.
    Arbring, Theresia
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    The impact of geometrical variations on the transport properties of organic electronic ion pumps2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The organic electronic ion pump (OEIP) is an electrically controlled polymer-based device that has the capability to interact with biological systems down to a single cell level by mimicking neural signalling. This is accomplished by translation of an electrical signal into a chemical output, such as ions and neurotransmitters. Because of the combined spatial and temporal precision, this is a technology with a promising future as an advanced therapeutic device. Depending on the application, the OEIP requires different geometries. Implants that will be used to control on a single cell level require very small dimensions, while for example extracorporeal mounted OIEPs, with only the delivery channel penetrating the skin, require much longer channels. Despite the application, it is necessary to have a good knowledge about the transport and delivery properties and how they change due to the geometry. These properties have been observed as very varying and unstable in early unpublished results, and these findings motivate this project. This project includes photolithographic fabrication and investigation of transport and delivery properties such as effective resistance, efficiency and stability of OEIPs with varying delivery channel lengths and widths. Shorter delivery channels show a consistent but relatively low efficiency. Delamination between different layers of the device is suspected as the cause. Initially, the longer delivery channels show a low functionality, most probably due to poor encapsulation. It is suggested that a soft, water-permeable plastic best encapsulates OEIPs that will be used as a medical implant, while a material impermeable to water, for example a metal, could successfully encapsulate OEIPs operating in air.

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  • 63.
    Arvidsson, Amanda
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Generic Control of Permanent Magnet Synchronous Motors2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    -

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  • 64. Order onlineBuy this publication >>
    Arwidson, Jonas
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Thermal Fatigue Life Prediction of Solder Joints in Avionics by Surrogate Modeling: A Contribution to Physics of Failure in Reliability Prediction2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Manufacturers of aerospace, defense, and high performance (ADHP) equipment are currently facing multiple challenges related to the reliability of electronic systems. The continuing reduction in size of electronic components combined with increasing clock frequencies and greater functionality, results in increased power density. As an effect, controlling the temperature of electronic components is central in electronic product development in order to maintain and potentially improve the reliability of the equipment. Simultaneously, the transition to lead-free electronic equipment will most probably propagate also to the ADHP industry. Compared to well-proven tin-lead solder, the knowledge about field operation reliability of lead-free solders is still limited, as well as the availability of damage evaluation models validated for field temperature conditions. Hence, the need to fill in several knowledge gaps related to reliability and reliability prediction of lead-free solder alloys is emphasized. Having perceived increasing problems experienced in the reliability of fielded equipment, the ADHP industry has suggested inclusion of physics-of-failure (PoF) in reliability prediction of electronics as one potential measure to improve the reliability of the electronic systems.

    This thesis aims to contribute to the development of reliable ADHP systems, with the main focus on electronic equipment for the aerospace industry. In order to accomplish this, the thesis provides design guidelines for power distribution on a double-sided printed circuit board assembly (PBA) as a measure to improve the thermal performance without increasing the weight of the system, and a novel, computationally efficient method for PoF-based evaluation of damage accumulation in solder joints in harsh, non-cyclic field operation temperature environments.

    Thermal fatigue failure mechanisms and state‑of‑the‑art thermal design and design tools are presented, with focus on the requirements that may arise from avionic use, such as low weight, high reliability, and ability to sustain functional during high vibration levels and high g-forces. Paper I, II, and III describes an in-depth investigation that has been performed utilizing advanced thermal modeling of power distribution on a double-sided PBA as a measure to improve the thermal performance of electronic modules.

    Paper IV contributes to increasing the accuracy of thermal fatigue life prediction in solder joints, by employing existing analytical models for predicting thermal fatigue life, but enhancing the prediction result by incorporating advanced thermal analysis in the procedure.

    Papers V and VI suggest and elaborate on a computational method that utilizes surrogate stress and strain modeling of a solder joint, to quickly evaluate the damage accumulated in a critical solder joint from non-cyclic, non-simplified field operation temperature profiles, with accuracy comparable to finite element modeling. The method has been tested on a ball grid array package with SnAgCu solder joints. This package is included in an extensive set of accelerated tests that helps to qualify certain packages and solder alloys for avionic use. The tests include -20°C to +80°C and -55°C to +125°C thermal cycling of a statistically sound population of a number of selected packages, assembled with SnAgCu, Sn100C, and SnPbAg solder alloys. Statistical analysis of the results confirms that the SnAgCu-alloy may outperform SnPbAg solder at moderate thermal loads on the solder joints.

    In Papers VII and VIII, the timeframe is extended to a future, in which validated life prediction models will be available, and the suggested method is expected to increase the accuracy of embedded prognostics of remaining useful thermal fatigue life of a critical solder joint.

    The key contribution of the thesis is the added value of the proposed computational method utilized in the design phase for electronic equipment. Due to its ability for time-efficient operation on uncompressed temperature data, the method gives contribution to the accuracy, and thereby also to the credibility, of reliability prediction of electronic packages in the design phase. This especially relates to applications where thermal fatigue is a dominant contributor to the damage of solder joints.

    List of papers
    1. CFD Analysis of an Avionic Module for Evaluating Power Distribution as a Thermal Management Measure for a Double-sided PCB
    Open this publication in new window or tab >>CFD Analysis of an Avionic Module for Evaluating Power Distribution as a Thermal Management Measure for a Double-sided PCB
    2007 (English)In: Semiconductor Thermal Measurement and Management Symposium, SEMI-THERM 2007, IEEE , 2007, p. 233-243Conference paper, Published paper (Refereed)
    Abstract [en]

    Thermal design aspects of an avionic module including fully populated PCBs housed in a sealed enclosure have been studied by means of computational fluid dynamics. Effect of power distribution between the sides of a double-sided PCB on the case temperature of surface-mounted components has been investigated within a proposed simulation strategy. Simulation-based guidelines have been developed for thermal design of avionic modules, regarding preferable power configuration on a double-sided PCB, representing an alternative approach to thermal management, as compared to introducing additional cooling devices.

    Place, publisher, year, edition, pages
    IEEE, 2007
    Series
    Semiconductor Thermal Measurement and Management Symposium, ISSN 1065-2221 ; 2007
    Keywords
    Avionics, thermal management, double-sided PCB, CFD, non-dominated designs
    National Category
    Other Electrical Engineering, Electronic Engineering, Information Engineering
    Identifiers
    urn:nbn:se:liu:diva-91902 (URN)10.1109/STHERM.2007.352429 (DOI)1-4244-09589-4 (print) (ISBN)1-4244-09589-4 (online) (ISBN)
    Conference
    23rd Annual IEEE Semiconductor Thermal Measurement and Management Symposium (SEMI-THERM 2007), March 18-22, San Jose, CA. USA
    Note

    At the time for thesis presentation publication was in status: Manuscript

    Available from: 2013-05-04 Created: 2013-05-04 Last updated: 2016-12-22Bibliographically approved
    2. An experimental setup for validating a CFD model of a double-sided PCB in a sealed enclosure at various power configurations
    Open this publication in new window or tab >>An experimental setup for validating a CFD model of a double-sided PCB in a sealed enclosure at various power configurations
    2005 (English)In: Proceedings of EuroSime 2005, Berlin: EuroSime , 2005, p. 127-133Conference paper, Published paper (Refereed)
    Abstract [en]

    A flexible experimental setup enabling power control of a fully populated double-sided PCB has been realized, and is described in detail. A CFD model of a double-sided PCB housed in a sealed enclosure has been validated in a 19°C environment by means of temperature and flow measurement. The difference between simulated and measured component temperatures has been within 10%. Potential errors both in the model and in the experiments have been discussed and their impact on temperatures has been numerically evaluated.

    Place, publisher, year, edition, pages
    Berlin: EuroSime, 2005
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-28747 (URN)10.1109/ESIME.2005.1502787 (DOI)13922 (Local ID)0-7803-9062-8 (ISBN)0-7803-9063-6 (ISBN)13922 (Archive number)13922 (OAI)
    Conference
    The 6th IEEE EuroSimE conference, April 18-20, Berlin, Germany
    Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2013-11-12Bibliographically approved
    3. Investigating the effect of power distribution on cooling a double-sided PCB: Numerical simulation and experiment
    Open this publication in new window or tab >>Investigating the effect of power distribution on cooling a double-sided PCB: Numerical simulation and experiment
    2005 (English)In: Proceedings of ASME Summer Heat Transfer Conference 2005, San Fransisco: ASME , 2005, p. 649-657Conference paper, Published paper (Refereed)
    Abstract [en]

    An experimental procedure for investigating the effect of power distribution on the cooling of a double-sided PCB is implemented. A number of computational fluid dynamics (CFD) models are validated by laboratory experiments performed in 19.5°C temperature environment. Case temperatures of surface-mounted components fully populating the PCB sides are measured and monitored in simulations. Different combinations of power distribution with other cooling methods, such as a heatsink tooled on a sealed or open enclosure, at natural or forced convection, are studied. Thermally efficient uniform and non-uniform power configurations are determined on a double sided PCB. It is concluded that managing power distribution on a double-sided PCB can be considered as a measure to improve the thermal performance of electronic modules.

    Place, publisher, year, edition, pages
    San Fransisco: ASME, 2005
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-28748 (URN)10.1115/HT2005-72549 (DOI)13923 (Local ID)0-7918-4734-9 (ISBN)0-7918-3762-9 (ISBN)13923 (Archive number)13923 (OAI)
    Conference
    ASME 2005 Summer Heat Transfer Conference collocated, with the ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems, Heat Transfer: Volume 4, San Francisco, California, USA, July 17–22, 2005
    Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2013-11-12Bibliographically approved
    4. On thermomechanical durability analysis combined with computational fluid dynamics thermal analysis
    Open this publication in new window or tab >>On thermomechanical durability analysis combined with computational fluid dynamics thermal analysis
    Show others...
    2007 (English)In: Proceedings of IMECE2007: ASME International Mechanical Engineering Congress and Exposition, American Society of Mechanical Engineers , 2007, p. 233-240Conference paper, Published paper (Refereed)
    Abstract [en]

    Results are presented on durability analysis of an electronic module subjected to thermal and power cycles, and vibration. A hierarchical analysis process for analyzing the durability of the module is described. The initial step is a transient thermal analysis of the unit in which the module is located. The three operating modes of the unit are modeled and analyzed using a commercially available computational fluid dynamics (CFD) tool. The tool generates a time history of the temperature at all points within the unit and module.

    The second step comprises exporting temperatures from the transient temperature analysis to a durability prediction tool. The temperatures calculated by the global analysis are mapped to the printed wiring assembly (PWA) mounted within the box, yielding the temperature distribution of the PWA as functions of time. The durability tool utilizes a modified Coffin Manson formula together with the transient temperature profile to estimate the durability of each lead and solder joint included in the module. Thermomechanical fatigue level of leads and solder joints within the unit are reported as a cumulative damage index (CDI). The CDI is the ratio of the number of cycles required for the test item to endure under a life time to the number of cycles the item is predicted to sustain before failure.

    Durability analysis of solder joint due to vibration is performed separately. The environment is specified according to the location where the unit is mounted. CDI due to vibration is added to form an overall CDI based on Miner’s rule.

    Place, publisher, year, edition, pages
    American Society of Mechanical Engineers, 2007
    Keywords
    Durability analysis, thermal cycling, vibration, transient power dissipation
    National Category
    Other Electrical Engineering, Electronic Engineering, Information Engineering
    Identifiers
    urn:nbn:se:liu:diva-91897 (URN)0791842991 (ISBN)
    Conference
    ASME International Mechanical Engineering Congress and Exposition (IMECE 2007), November 11–15, 2007, Seattle, Washington, USA
    Available from: 2013-05-04 Created: 2013-05-04 Last updated: 2013-12-03Bibliographically approved
    5. A computational method for evaluating the damage in a solder joint of an electronic package subjected to thermal loads
    Open this publication in new window or tab >>A computational method for evaluating the damage in a solder joint of an electronic package subjected to thermal loads
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Purpose – The purpose of this paper is to introduce a novel computational method to evaluate damage accumulation in a solder joint of an electronic package, when exposed to operating temperature environment. A procedure to implement the method is suggested, and a discussion of the method and its possible applications is provided in the paper.

    Originality/value – The method enables increased accuracy in thermal fatigue life prediction of solder joints. Combined with other failure mechanisms, it may contribute to the accuracy of reliability assessment of electronic packages.

    Design/methodology/approach – Methodologically, interpolated response surfaces based on specially designed finite element simulation runs, are employed to compute a damage metric at regular time intervals of an operating temperature profile. The developed method has been evaluated on a finite-element model of a lead-free PBGA256 package, and accumulated creep strain energy density has been chosen as damage metric.

    Findings – The method has proven to be two orders of magnitude more computationally efficient compared to finite element simulation. A general agreement within 3% has been found between the results predicted with the new method, and finite element simulations when tested on a number of temperature profiles from an avionic application. The solder joint temperature ranges between +25°C and +75°C.

    Practical implications – The method can be implemented as part of reliability assessment of electronic packages in the design phase.

    Keywords
    Computational method, electronic package, finite element analysis, thermal fatigue, operating temperature environment, lead-free solder
    National Category
    Other Electrical Engineering, Electronic Engineering, Information Engineering
    Identifiers
    urn:nbn:se:liu:diva-91898 (URN)
    Available from: 2013-05-04 Created: 2013-05-04 Last updated: 2013-05-08Bibliographically approved
    6. Investigation on thermal fatigue of SnAgCu, Sn100C, and SnPbAg solder joints in varying temperature environments
    Open this publication in new window or tab >>Investigation on thermal fatigue of SnAgCu, Sn100C, and SnPbAg solder joints in varying temperature environments
    Show others...
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Thermal cycling tests have been performed for a range of electronic components intended for avionic applications, assembled with SAC305, SN100C and SnPbAg solder alloys. Two temperature profiles have been used, the first ranging between -20°C to +80°C (TC1), and the second between -55°C and +125°C (TC2). High level of detail is provided for the solder alloy composition and the component package dimensions, and statistical analysis, partially supported by FE modeling, is reported. The test results confirm the feasibility of SAC305 as a replacement for SnPbAg under relatively benign thermomechanical loads. Furthermore, the test results serve as a starting point for estimation of damage accumulation in a critical solder joint in field conditions, with increased accuracy by avoiding data reduction. A computationally efficient method that was earlier introduced by the authors and tested on relatively mild temperature environments has been significantly improved to become applicable on extended temperature range, and it has been applied to a PBGA256 component with SAC305 solder in TC1 conditions. The method, which utilizes interpolated response surfaces generated by finite element modeling, extends the range of techniques that can be employed in the design phase to predict thermal fatigue of solder joints under field temperature conditions.

    Keywords
    Thermal cycling tests, lead-free solder, reliability prediction, surrogate modeling
    National Category
    Other Electrical Engineering, Electronic Engineering, Information Engineering
    Identifiers
    urn:nbn:se:liu:diva-91899 (URN)
    Available from: 2013-05-04 Created: 2013-05-04 Last updated: 2013-05-08Bibliographically approved
    7. Prognostics of Thermal Fatigue Failure of Solder Joints in Avionic Equipment
    Open this publication in new window or tab >>Prognostics of Thermal Fatigue Failure of Solder Joints in Avionic Equipment
    2012 (English)In: IEEE Aerospace and Electronic Systems Magazine, ISSN 0885-8985, E-ISSN 1557-959X, Vol. 27, no 4, p. 16-24Article in journal (Refereed) Published
    Abstract [en]

    A practical method has been suggested for solder joint thermal fatigue prognostics, which enables real-time fatigue calculations based on uncompressed temperature data embedded in a host system that performs safety-critical operations. The accuracy of the prognosticated remaining useful life depends on the level of details captured in the model, and the level of confidence from validation efforts.

    Place, publisher, year, edition, pages
    IEEE, 2012
    Keywords
    Thermal fatigue prognostics, physics-of-failure, electronics, avionics, solder joints.
    National Category
    Other Electrical Engineering, Electronic Engineering, Information Engineering
    Identifiers
    urn:nbn:se:liu:diva-91900 (URN)10.1109/MAES.2012.6203714 (DOI)
    Available from: 2013-05-04 Created: 2013-05-04 Last updated: 2017-12-06Bibliographically approved
    8. An approach to life consumption monitoring of solder joints in operating temperature environment
    Open this publication in new window or tab >>An approach to life consumption monitoring of solder joints in operating temperature environment
    2012 (English)In: Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE), 2012, IEEE , 2012, p. 1-8Conference paper, Published paper (Refereed)
    Abstract [en]

    This paper elaborates the 3T-approach to life consumption monitoring of solder joints in operating temperature environment without requiring simplification of operating loads.

    An overview of the 3T-approach is provided including assumptions made for a proposed realization in an avionic application. Associated implementation routines are highlighted and exemplified for a lead-free PBGA256 package with creep strain energy density (SEDcr) as damage metric.

    Factors that affect the prediction accuracy are investigated. A data resolution has been determined that delivers response surfaces that provide results comparable to 3-D finite-element (FE) simulations, while bearing two orders of magnitude higher computational efficiency.

    A stress-free temperature modification routine is proposed and proves to further mitigate accuracy problems.

    Place, publisher, year, edition, pages
    IEEE, 2012
    Keywords
    Life consumption monitoring, solder joints, avionics, thermal fatigue
    National Category
    Other Electrical Engineering, Electronic Engineering, Information Engineering
    Identifiers
    urn:nbn:se:liu:diva-91901 (URN)10.1109/ESimE.2012.6191699 (DOI)978-1-4673-1512-8 (ISBN)
    Conference
    13th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE 2012), April 16-18, Cascais, Portugal
    Available from: 2013-05-04 Created: 2013-05-04 Last updated: 2013-05-20Bibliographically approved
    Download full text (pdf)
    Thermal Fatigue Life Prediction of Solder Joints in Avionics by Surrogate Modeling: A Contribution to Physics of Failure in Reliability Prediction
    Download (pdf)
    omslag
  • 65.
    Asghar, M.
    et al.
    Islamia University of Bahawalpur, Pakistan.
    Mahmood, K.
    Islamia University of Bahawalpur, Pakistan.
    Hasan, M. A.
    University of N Carolina, NC 28223 USA.
    Ferguson, I. T.
    University of N Carolina, NC 28223 USA.
    Tsu, R.
    University of N Carolina, NC 28223 USA.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Characterization of deep acceptor level in as-grown ZnO thin film by molecular beam epitaxy2014In: Chinese Physics B, ISSN 1009-1963, E-ISSN 1741-4199, Vol. 23, no 9, p. 097101-Article in journal (Refereed)
    Abstract [en]

    We report deep level transient spectroscopy results from ZnO layers grown on silicon by molecular beam epitaxy (MBE). The hot probe measurements reveal mixed conductivity in the as-grown ZnO layers, and the current-voltage (I-V) measurements demonstrate a good quality p-type Schottky device. A new deep acceptor level is observed in the ZnO layer having activation energy of 0.49 +/- 0.03 eV and capture cross-section of 8.57 +/- 10(-18) cm(2). Based on the results from Raman spectroscopy, photoluminescence, and secondary ion mass spectroscopy (SIMS) of the ZnO layer, the observed acceptor trap level is tentatively attributed to a nitrogen-zinc vacancy complex in ZnO.

  • 66.
    Asif, Muhammad
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Zinc Oxide Nanostructure Based Electrochemical Sensors and Drug Delivery to Intracellular Environments2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The nanoscale science and nanostructure engineering have well established in the fabrication of novel electrochemical biosensors with faster response and higher sensitivity than of planar sensor configurations. Moreover nanostructures are suggested and used as efficient carrier of photosensitizers for cancerous cell treatment. The semi-conductor zinc oxide (ZnO) nanostructures have attracted much interest because of its unique piezoelectric, polar semiconducting, large surface area, catalytic properties, and being biosafe and biocompatible combined with the easiness of growth. This implies that ZnO nanostructures have a wide range of applications in optoelectronics, sensors, transducers, energy conversion and medical sciences. The aim of this study is to highlight recent developments in materials and techniques for electrochemical biosensing, photodynamic therapy, design, operation, and fabrication. The sensors in this study were used to detect and monitor real changes of metal ions and glucose across human fat cells and frog cells using changes in the electrochemical potential at the interface to the intracellular microenvironments. This thesis relates specifically to “zinc oxide nanostructure based electrochemical sensors and drug delivery to intracellular environments” for biological, biochemical and chemical applications.

    The first part of the thesis presents extra and intracellular studies on metal ions such as Ca2+, Mg2+, and Na+…..etc selectively sensed by using ZnO nanorods grown on the tip of a borosilicate glass capillary (0.7 μm in diameter) with the aim to produce proto-type electrochemical extra/intracellular biosensors. The single human adipocyte and frog oocyte cells were used to selectively measure the intracellular free metal ions concentration. To make the sensors selective for metal ions with sufficient selectivity and stability, plastic membrane coatings containing specific ionophores were applied. These functionalized ZnO nanorods sensors showed high sensitivity and good stability with linear electrochemical potential versus a wide metal ion concentration range of interest. The measured intracellular values were consistent with values reported in the literature. Furthermore we have successfully determined that the intracellular potassium (K+) concentration decrease is not obligatory for apoptosis. The aim of this study is to show the possibility of using K+ selective microelectrode to detect and monitor intracellular changes of K+ concentration during injection of various test solution and chemically induced apoptosis in Xenopus laevis oocytes parallel with electrophysiological measurements to verify the accuracy.

    The second part, presents the calcium ion (Ca2+) detection using functionalized ZnO nanorods attached as an extended gate metal oxide semiconductor field effect transistor (MOSFET). The electrochemical response was coupled directly to the gate of a commercial MOSFET to study the I-V characterization. Here we verified that ZnO nanorods grown on any thin wire can be combined with conventional electronic component to produce a sensitive and selective biosensor.

    In the third part, we have performed the experiment to determine glucose concentration intracellularly and in airway surface liquid (ASL) with functionalized ZnO nanorod-coated microelectrodes. In this study, the GOD enzyme was immobilised electrostatically, drawing on the fact that there is a large difference in the isoelectric points of ZnO and glucose oxidase. Insulin has been found to affect the glucose uptake in human adipocytes and frog Xenopus laevis. The large size of these cells makes it possible to microinject specific reagents that interrupt or activate signal transmission to glucose. The measured glucose concentration in human adipocytes or frog oocytes and ASL using our ZnO nanorod sensor was consistent with values of glucose concentration reported in the literature by using other indirect techniques.

    The fourth and final part covers the application of ZnO nanorods to cancer cells for photodynamic therapy. The ZnO nanorods were conjugated with protoporphyrin for local mediated photochemistry and efficient treatment of a single cancer cell. The ZnO nanorods were used as an efficient photosensitizer carrier system and at the same time providing intrinsic white light to achieve necrosis of the cancer cell. Breast cancer cells were used to study the catalytic effect of ZnO for treatment. The grown ZnO nanorods were conjugated with protoporphyrin dimethyl ester (PPDME), which absorbs the light emitted by the ZnO nanorods and cause the cytotoxicity which appears to involve the generation of reactive singlet oxygen inside the cell.

    List of papers
    1. Studies on Calcium Ion Selectivity of ZnO Nanowire Sensors Using Ionophore Membrane Coatings
    Open this publication in new window or tab >>Studies on Calcium Ion Selectivity of ZnO Nanowire Sensors Using Ionophore Membrane Coatings
    Show others...
    2008 (English)In: Research Letters in Nanotechnology, ISSN 1687-6849, Vol. 2008, no Article ID 701813Article in journal (Refereed) Published
    Abstract [en]

    Zinc oxide nanorods with 100nm diameter and 900nm length were grown on the surface of a silver wire (0.25mm in diameter)

    with the aim to produce electrochemical nanosensors. It is shown that the ZnO nanorods exhibit a Ca2+-dependent electrochemical

    potentiometric behavior in an aqueous solution. The potential difference was found to be linear over a large logarithmic

    concentration range (1 μM to 0.1 M) using Ag/AgCl as a reference electrode and the response time was less than one minute.

    In order to adapt the sensors for calcium ion measurements in biological fluids with sufficient selectivity and stability, plastic

    membrane coatings containing ionophores were applied. These functionalized ZnO nanorods sensors showed a high sensitivity

    (26.55 mV/decade) and good stability.

    Place, publisher, year, edition, pages
    Hindawi Publishing Corporation, 2008
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-19514 (URN)10.1155/2008/701813 (DOI)
    Available from: 2009-06-25 Created: 2009-06-25 Last updated: 2014-01-15Bibliographically approved
    2. Functionalized zinc oxide nanorod with ionophore-membrane coatingas an intracellular Ca2+ selective sensor
    Open this publication in new window or tab >>Functionalized zinc oxide nanorod with ionophore-membrane coatingas an intracellular Ca2+ selective sensor
    Show others...
    2009 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 95, no 2, p. 23703-Article in journal (Refereed) Published
    Abstract [en]

    The tip of a borosilicate glass capillary with functionalized hexagonal ZnO nanorods was used to make a sensitive electrochemical intracellular Ca2+ sensor. To adjust the sensor for Ca2+ measurements with sufficient selectivity and stability, polyvinyl chloride (PVC) membrane containing Ca2+ ionophores were coated on the surface. The membrane covered ZnO nanorods exhibited a Ca2+-dependent electrochemical potential difference versus an Ag/AgCl reference electrode. The potential difference was linear over a large concentration range (100 nM to 10 mM). The measurements of Ca2+ concentrations using our ZnO nanorods sensor in human fat cells or in frog egg cells were consistent with values of Ca2+ concentrations reported in the literature. This nanoelectrode device paves the way to measurements of intracellular biochemical species in specific locations within single living cells.

    Place, publisher, year, edition, pages
    EBSCO/American Institute of Physics, 2009
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-19516 (URN)10.1063/1.3176441 (DOI)
    Note
    On the day of the defence date the status of this article was Submitted.Available from: 2009-06-25 Created: 2009-06-25 Last updated: 2018-01-25Bibliographically approved
    3. Selective calcium ion detection with functionalized ZnO nanorods-extendedgate MOSFET
    Open this publication in new window or tab >>Selective calcium ion detection with functionalized ZnO nanorods-extendedgate MOSFET
    2009 (English)In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 24, no 11, p. 3379-3382Article in journal (Refereed) Published
    Abstract [en]

    Zinc oxide nanorod-extended gate field effect transistor (MOSFET) is demonstrated for the detection of calcium (Ca2+) ions. ZnO nanorods were grown on the surface of a silver wire to produce an electrochemical nanosensor for selectively detecting Ca2+. The electrochemical response from the interaction between the ZnO nanorods and Ca2+ in an aqueous solution is coupled directly to the gate of a field effect transistor (MOSFET). The induced voltage change on the gate results in a measureable current response. In order to adapt the sensors for Ca2+ ions measurements in biological fluids with sufficient selectivity and stability, a plastic membrane coating containing ionophores was applied on the nanorods. The sensor exhibited a linear response within the range of interest from 1 μM to 1 mM. This work demonstrates a simple technique for sensitive detection of Ca2+ ions by efficient transfer of the chemical response directly to a standard electronic component producing a low impedance signal.

    Place, publisher, year, edition, pages
    ELSEVIER, 2009
    Keywords
    Calcium ions, electrochemical sensor, ZnO nanorods, MOSFET
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-19515 (URN)10.1016/j.bios.2009.04.011 (DOI)
    Available from: 2009-06-25 Created: 2009-06-25 Last updated: 2017-12-13Bibliographically approved
    4. Intracellular potassium (K+) concentration decrease is not obligatory for apoptosis
    Open this publication in new window or tab >>Intracellular potassium (K+) concentration decrease is not obligatory for apoptosis
    Show others...
    2011 (English)In: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 286, no 46, p. 39823-39828Article in journal (Refereed) Published
    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+.

    Place, publisher, year, edition, pages
    American Society for Biochemistry and Molecular Biology, 2011
    Keywords
    Caspase-3 activation, Electrophysiology, Intracellular K+ concentrations, K+-selective microelectrode, Xenopus laevis oocytes
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-68853 (URN)10.1074/jbc.M111.262725 (DOI)000296925700016 ()
    Note
    Funding agencies|Swedish Research Council||Swedish Heart-Lung Foundation||Swedish Brain Foundation||County Council of Ostergotland, King Gustaf V and Queen Victorias Freemasons Foundation||Swedish Society for Medical Research||Available from: 2011-06-08 Created: 2011-06-08 Last updated: 2018-01-25Bibliographically approved
    5. Functionalised ZnO-nanorod-based selective electrochemical sensor for intracellular glucose
    Open this publication in new window or tab >>Functionalised ZnO-nanorod-based selective electrochemical sensor for intracellular glucose
    Show others...
    2010 (English)In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 25, no 10, p. 2205-2211Article in journal (Refereed) Published
    Abstract [en]

    In this article, we report a functionalised ZnO-nanorod-based selective electrochemical sensor for intracellular glucose. To adjust the sensor for intracellular glucose measurements, we grew hexagonal ZnO nanorods on the tip of a silver-covered borosilicate glass capillary (0.7 mu m diameter) and coated them with the enzyme glucose oxidase. The enzyme-coated ZnO nanorods exhibited a glucose-dependent electrochemical potential difference versus an Ag/AgCl reference microelectrode. The potential difference was linear over the concentration range of interest (0.5-1000 mu M). The measured glucose concentration in human adipocytes or frog oocytes using our ZnO-nanorod sensor was consistent with values of glucose concentration reported in the literature; furthermore, the sensor was able to show that insulin increased the intracellular glucose concentration. This nanoelectrode device demonstrates a simple technique to measure intracellular glucose concentration.

    Place, publisher, year, edition, pages
    Elsevier Science B.V., Amsterdam., 2010
    Keywords
    ZnO nanorods; Functionalisation; Intracellular glucose; Electrochemical sensor
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-58381 (URN)10.1016/j.bios.2010.02.025 (DOI)000278702600004 ()
    Note
    Original Publication: Muhammad Asif, Syed Usman Ali, Omer Nour, Magnus Willander, Cecilia Brännmark, Peter Strålfors, Ulrika Englund, Fredrik Elinder and Bengt Danielsson, Functionalised ZnO-nanorod-based selective electrochemical sensor for intracellular glucose, 2010, Biosensors & bioelectronics, (25), 10, 2205-2211. http://dx.doi.org/10.1016/j.bios.2010.02.025 Copyright: Elsevier Science B.V., Amsterdam. http://www.elsevier.com/ Available from: 2010-08-13 Created: 2010-08-11 Last updated: 2018-01-25
    6. In situ quantification of glucose concentration in airway surface liquid with functionalized ZnO nanorod-coated microelectrodes
    Open this publication in new window or tab >>In situ quantification of glucose concentration in airway surface liquid with functionalized ZnO nanorod-coated microelectrodes
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    The surface of the airways that conduct gases into and out of the lungs has components that are crucial in protecting the host from inhaled and aspirated pathogens. The thin (4-7µm height) layer of airway surface liquid (ASL) that lines the airways has physicochemical properties that are important for normal function of these antimicrobial components. Among these properties, low glucose concentration is required for normal antimicrobial activity. Current methods for assessing the ASL have important flaws (temporal resolution, dilution factors, collection volume), which have been a recurring obstacle for understanding diseases in which ASL composition is abnormal. To circumvent these problems, microelectrodes coated with ZnO nanorods and immobilized glucose oxidase was used to determine glucose concentration in ASL of well-differentiated cultures of human airway epithelia. The sensor responded to glucose linearly over a concentration range of 0.128 to 8mM and the effects of electroactive interferents were minimal. The measured concentration of glucose in ASL was consistent with values previously reported. This method confirms the presence of a transepithelial glucose concentration gradient in human airway epithelia and is an important step towards characterizing the physicochemical properties of ASL and understanding diseases caused by changes in ASL composition.

    Keywords
    Zinc Oxide, Mucosa, Lung, Electrode, Glucose
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-68854 (URN)
    Available from: 2011-06-08 Created: 2011-06-08 Last updated: 2014-01-15Bibliographically approved
    7. Intracellular ZnO Nanorods Conjugated with Protoporphyrin for Local Mediated Photochemistry and Efficient Treatment of Single Cancer Cell
    Open this publication in new window or tab >>Intracellular ZnO Nanorods Conjugated with Protoporphyrin for Local Mediated Photochemistry and Efficient Treatment of Single Cancer Cell
    Show others...
    2010 (English)In: NANOSCALE RESEARCH LETTERS, ISSN 1931-7573, Vol. 5, no 10, p. 1669-1674Article in journal (Refereed) Published
    Abstract [en]

    ZnO nanorods (NRs) with high surface area to volume ratio and biocompatibility is used as an efficient photosensitizer carrier system and at the same time providing intrinsic white light needed to achieve cancer cell necrosis. In this letter, ZnO nanorods used for the treatment of breast cancer cell (T47D) are presented. To adjust the sample for intracellular experiments, we have grown the ZnO nanorods on the tip of borosilicate glass capillaries (0.5 mu m diameter) by aqueous chemical growth technique. The grown ZnO nanorods were conjugated using protoporphyrin dimethyl ester (PPDME), which absorbs the light emitted by the ZnO nanorods. Mechanism of cytotoxicity appears to involve the generation of singlet oxygen inside the cell. The novel findings of cell-localized toxicity indicate a potential application of PPDME-conjugated ZnO NRs in the necrosis of breast cancer cell within few minutes.

    Place, publisher, year, edition, pages
    Springer Science Business Media, 2010
    Keywords
    ZnO nanorods, Cancer cell necrosis, Photodynamic therapy, Protoporphyrin dimethyl ester
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-61180 (URN)10.1007/s11671-010-9693-z (DOI)000283124800022 ()21076704 (PubMedID)
    Available from: 2010-11-05 Created: 2010-11-05 Last updated: 2014-09-25
    8. Growth and Structure of ZnO Nanorods on a Sub-Micrometer Glass Pipette and Their Application as Intracellular Potentiometric Selective Ion Sensors
    Open this publication in new window or tab >>Growth and Structure of ZnO Nanorods on a Sub-Micrometer Glass Pipette and Their Application as Intracellular Potentiometric Selective Ion Sensors
    Show others...
    2010 (English)In: Materials, ISSN 1996-1944, Vol. 3, p. 4657-4667Article in journal (Refereed) Published
    Abstract [en]

    This paper presents the growth and structure of ZnO nanorods on a sub-micrometer glass pipette and their application as an intracellular selective ion sensor. Highly oriented, vertical and aligned ZnO nanorods were grown on the tip of a borosilicate glass capillary (0.7 μm in diameter) by the low temperature aqueous chemical growth (ACG) technique. The relatively large surface-to-volume ratio of ZnO nanorods makes them attractive for electrochemical sensing. Transmission electron microscopy studies show that ZnO nanorods are single crystals and grow along the crystal’s c-axis. The ZnO nanorods were functionalized with a polymeric membrane for selective intracellular measurements of Na

     

    +. The membrane-coated ZnO nanorods exhibited a Na+-dependent electrochemical potential difference versus

    an Ag/AgCl reference micro-electrode within a wide concentration range from 0.5 mM to 100 mM. The fabrication of functionalized ZnO nanorods paves the way to sense a wide range of biochemical species at the intracellular level.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-64303 (URN)10.3390/ma3094657 (DOI)
    Available from: 2011-01-21 Created: 2011-01-18 Last updated: 2018-01-25Bibliographically approved
    Download (pdf)
    omslag
  • 67.
    Asif, Muhammad
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology. COMSATS institute of Information Technology, Lahore, Pakistan.
    Elinder, Fredrik
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Electrochemical Biosensors Based on ZnO Nanostructures to Measure Intracellular Metal Ions and Glucose2011In: Journal of Analytical & Bioanalytical Techniques, ISSN 2155-9872, Vol. S7, no 003, p. 1-9Article in journal (Refereed)
    Abstract [en]

    Zinc oxide (ZnO) nanostructures have attracted much interest for intracellular electrochemical measurements because of its large surface area, and its biocompatible properties. To design intracellular biosensors for metal ions and glucose, we grew ZnO nanorods on the tip of borosilicate glass capillaries (0.7μm in diameter) and characterized the nano-scale structure with field-emission scanning electron microscopy and high-resolution transmission electron microscopy. The ZnO nanorods were functionalized accordingly for intracellular free metal ions or glucose measurements. Selectivity was achieved by using a metal-ion selective plastic membrane or glucose oxidase enzyme for glucose measurements. These functionalized ZnO nanorods showed high sensitivity and good biocompatibility for intracellular environments. Human adipocytes and frog oocytes were used for determinations of intracellular free metal ions and glucose concentrations. In this review, we discuss the simple and direct approach for intracellular measurements using ZnO nanostructure-based potentiometric biosensors for clinical and non-clinical applications. The performance of ZnO nanostructure-based intracellular sensor can be improved through engineering of morphology, effective surface area, functionality, and adsorption/desorption capability. This study paves the way to find applications in biomedicine by using this simple and miniaturized biosensing device

  • 68.
    Asif, Muhammad H.
    et al.
    COMSATS Institute Informat Technology, Pakistan; Acromed Invest AB, Sweden.
    Danielsson, Bengt
    Acromed Invest AB, Sweden.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    ZnO Nanostructure-Based Intracellular Sensor2015In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 15, no 5, p. 11787-11804Article, review/survey (Refereed)
    Abstract [en]

    Recently ZnO has attracted much interest because of its usefulness for intracellular measurements of biochemical species by using its semiconducting, electrochemical, catalytic properties and for being biosafe and biocompatible. ZnO thus has a wide range of applications in optoelectronics, intracellular nanosensors, transducers, energy conversion and medical sciences. This review relates specifically to intracellular electrochemical (glucose and free metal ion) biosensors based on functionalized zinc oxide nanowires/nanorods. For intracellular measurements, the ZnO nanowires/nanorods were grown on the tip of a borosilicate glass capillary (0.7 mu m in diameter) and functionalized with membranes or enzymes to produce intracellular selective metal ion or glucose sensors. Successful intracellular measurements were carried out using ZnO nanowires/nanorods grown on small tips for glucose and free metal ions using two types of cells, human fat cells and frog oocytes. The sensors in this study were used to detect real-time changes of metal ions and glucose across human fat cells and frog cells using changes in the electrochemical potential at the interface of the intracellular micro-environment. Such devices are helpful in explaining various intracellular processes involving ions and glucose.

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  • 69.
    Asif, Muhammad H.
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Strålfors, Peter
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Danielsson, Bengt
    Lund University, Sweden.
    Zinc Oxide Nanorods and their Application to Intracellular Glucose Measurements2012In: Nanotechnology and Nanomedicine in Diabetes / [ed] Lan-Anh Le, Ross J. Hunter, Victor R. Preedy, CRC Press, 2012, p. 126-146Chapter in book (Other academic)
  • 70.
    Atif, M.
    et al.
    King Saud University, Saudi Arabia; National Institute Laser and Optron, Pakistan .
    Alsalhi, M. S.
    King Saud University, Saudi Arabia .
    Khun, Kimleang
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    The synthesis and optical characterization of well aligned ZnO nanorods using seed layer of Mn3O4 nanoparticles2014In: Optoelectronics and Advanced Materials Rapid Communications, ISSN 1842-6573, E-ISSN 2065-3824, Vol. 8, no 7-8, p. 643-646Article in journal (Refereed)
    Abstract [en]

    In this study, vertically aligned ZnO nanorods were fabricated by hydrothermal growth method using manganese oxide Mn3O4 nanoparticles as a seed layer. X-ray diffraction and Raman studies have shown the nano meter size of Mn3O4 nanoparticles. ZnO nanorods were characterized by field emission scanning electron microscopy and X-ray diffraction techniques. The prepared ZnO nanorods are highly dense, uniform and verily aligned and possess good crystal quality. Photoluminescence analysis has demonstrated that the ZnO nanorods exhibit deep level emission in green region due to oxygen vacancy related emission and the orange/red region is resulted due to interstitial oxygen defects related emission. This method for the fabrication of well aligned ZnO nanorods can be adapted for the development of optoelectronic devices.

  • 71.
    Azahar Ali, Md.
    et al.
    CSIR, India; Indian Institute Technology Hyderabad, India.
    Srivastava, Saurabh
    CSIR, India; Delhi Technology University, India.
    Agrawal, Ved V.
    CSIR, India.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    John, Renu
    Indian Institute Technology Hyderabad, India.
    Malhotra, Bansi D.
    Delhi Technology University, India.
    A biofunctionalized quantum dot-nickel oxide nanorod based smart platform for lipid detection2016In: Journal of materials chemistry. B, ISSN 2050-750X, E-ISSN 2050-7518, Vol. 4, no 15, p. 2706-2714Article in journal (Refereed)
    Abstract [en]

    A reagent-free, low-cost and sensitive immunosensor has been fabricated using anti-apolipoprotein B (AAB) conjugated L-cysteine in situ capped cadmium sulfide quantum dots (CysCdS QDs) bound to nickel oxide nanorods (nNiO) for detection of low density lipoprotein (LDL) molecules in human serum samples. The structural and morphological properties of AAB conjugated CysCdS QDs and nNiO have been investigated using electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and UV-visible techniques. In this immunosensor, the synthesized NiO nanorods act as mediators that allow the direct electron transfer due to their channeling effect resulting in a mediator-free biosensor. This mediator-free CysCdS-NiO based immunosensor shows improved characteristics such as a good sensitivity of 32.08 mu A (mg dl(-1))(-1) cm(-2) compared to that based on nNiO (1.42 mA (mg dl(-1))(-1) cm(-2)) alone for detection of lipid (LDL) molecules over a wide concentration range, 5-120 mg dl(-1) (0.015-0.36 mu M). The kinetic analysis yields an association constant (K-a) of 3.24 kM(-1) s(-1), indicating that the antibody conjugated CysCdS-NiO platform has a strong affinity towards lipid molecules. The excellent electron transport properties of the CysCdS-NiO nanocomposite in this immunosensor reveal that it provides an efficient platform for routine quantification of LDL molecules in real samples.

  • 72.
    Aziz, Awais
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Miniaturization of UWB RF Six-Port Circuit at 6-8.5 (6-9) GHz using Multi-Layer Microvia Printed circuit Board with Symmetric Stack Approach2011Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Technological advancements in the field of electronic design are greatly being triggered by the fact that communication devices in general and wireless communication devices in particular are required to be miniaturized in order to increase mobility and flexibility.

    This thesis work revolves around the study and simulation based design of an efficient Six Port Correlator circuit to support miniaturization for handheld devices in the European Ultrawideband (UWB) range of 6-9 GHz.

    Firstly, design of a six-port correlator circuitry is carried out by performing simulations in Advanced Design System (ADS) for two metal layers design, while achieving the desired phase and amplitude imbalance in the 6-9 GHz range. After this design is mapped on to  Printed Circuit Board (PCB) in order to compare the simulated and measured results.

    In the second part single metal layer design is converted on to multiple layers with symmetric stack by using microvia technology in order to achieve the required bandwidth i.e. cover the 6-9 GHz frequency band. The simulations for the multiple layers are also done in ADS.

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  • 73.
    Azoidou, Eva
    et al.
    ABB Corporate Research, Västerås Sweden.
    Pang, Zhibo
    Corporate Research, ABB AB, Västerås Sweden.
    Liu, Yu
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Lan, Dapeng
    ABB Corporate Research Center Sweden, Västerås, Sweden.
    Bag, Gargi
    Industrial Communication, ABB,Västerås Sweden.
    Gong, Shaofang
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Battery Lifetime Modeling and Validation of Wireless Building Automation Devices in Thread2018In: IEEE Transactions on Industrial Informatics, ISSN 1551-3203, E-ISSN 1941-0050, Vol. 14, no 7, p. 2869-2880Article in journal (Refereed)
    Abstract [en]

    The need for energy efficiency in wireless communication is prevalent in all areas, but to an even greater extent in low-power and lossy networks (LLN) that rely on resource constrained devices. This article seeks to address the problem of modeling the battery lifetime of a duty-cycled node, participating in a wireless sensor network that is typically used in smart home and building applications. Modeling in MATLAB and experimentation with prototype testing are employed to predict and validate. Various scenarios including sleepy end devices in a wireless sensor network are modeled and validated. They range from variable wake-up frequency and packet payload transmission to increasing network contention with the addition of network load. A comprehensive analysis of the main factors contributing to wasteful energy usage is provided. It can be concluded that the model can estimate the battery lifetime under different testing scenarios with an error rate less than 5 %.

  • 74.
    Baaklini, Fredrik
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Bohman, Nicklas
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Design of a high-precision energy meter according to the Measuring Instruments Directive2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis investigates how an energy meter should be constructed in order to apply to the Measurement Instrument Directive. The measuring instrument directive is a statutory industry standard. All meters used for billing purposes must abide by this standard. Multiple systems were investigated in order to find the optimal system according to the agreed upon demands. Each system is presented individually and need to be able to withstand 230V and 35A. The system which fulfills the demands the best is implemented. The choosen system is based around the M90E32AS and Atmega328pb IC:s from Microchip. The sensors used are current transformers and voltage dividers. The M90E32AS samples data from the sensors and forwards it to the Atmega328pb where they can be read by a computer. Communication is conducted via SPI (Serial Peripheral Interface). Isolation is needed to provide protection to low voltage components and other equipment. Because of this the transformers and optocouplers are used. The end result is a functioning energy meter. It measures voltage and current in a satisfying way with a very small margin om error. According to the test made regarding energymetering the measurement error is just above 1%. This is a bigger error than what was wanted but the tests are not very precise and the error is probably smaller in reality.

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    Design of a high-precision energy meter according to the Measuring Instruments Directive
  • 75.
    Babar, Haji Akbar
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Khattak, Atif
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Design of Dual Band Patch Antenna Array2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Low profile antennas are very useful in applications such as missile, aircraft, cellular applications and satellites, because in these types of applications, some commonly important constraints are cost, size, weight, performance and easy installation. Microstrip patch antenna fits quite comfortably in this category.

    This thesis work aimed to design the dual band microstrip patch antenna arrays operating at frequencies of 3.5 GHz and 5.0 GHz. Two schemes were used to design the antenna array which is the antenna array with same patch size and antenna array with alternating patch size. Different array configuration with 2, 4, 8 and 16 elements were designed and simulated in Agilent Inc EDA tool ADS using Roger RO4350B substrate with a height of 1.524 mm, and transmission-line model was used for the analysis. Array configuration with 2, 4 and 8 elements were fabricated, and results were measured with the help of the network analyzer in the Lab. Distinct antenna parameters were studied such as VSWR, impedance bandwidth, gain, directivity, antenna radiation efficiency, axial ratio and radiation pattern to evaluate the performance of antennas. Focusing on impedance bandwidth it can be claimed that the microstrip patch antenna arrays have better performance as compared to the single microstrip patch antenna designed.

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  • 76.
    Baillie, Caroline
    et al.
    Queen's University, Canada.
    Bernhard, Jonte
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Editorial: Educational research impacting engineering education2009In: European Journal of Engineering Education, ISSN 0304-3797, E-ISSN 1469-5898, Vol. 34, no 4, p. 291-294Article in journal (Other academic)
  • 77.
    Baillie, Caroline
    et al.
    Queen's University, Canada.
    Bernhard, JonteLinköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Special Issue: Educational research impacting engineering education2009Collection (editor) (Refereed)
  • 78.
    Bajpai, O.
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Östh, Joakim
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Gong, Shaofang
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Differential six-port modulator in 2011 International Conference on Wireless Communications and Signal Processing, WCSP 2011, vol , issue , pp2011In: 2011 International Conference on Wireless Communications and Signal Processing, WCSP 2011, 2011Conference paper (Refereed)
    Abstract [en]

    A differential six-port modulator for the 7-8 GHz band is reported for the first time. It is composed of a differential six-port correlator with cold-mode field effect transistors used as impedance terminations, controlled via baseband signal on the gate to source terminal. It is fabricated using double-sided parallel-strip lines. The differential modulator has the advantage of low power consumption, compactness and high signal to noise ratio. A prototype has been fabricated and data transmission with 256-quadrature amplitude modulation at 50 Msymbol/s is demonstrated. © 2011 IEEE.

  • 79.
    Baloach, Qurrat-ul-ain
    et al.
    University of Sindh, Pakistan.
    Nafady, Ayman
    King Saud University, Saudi Arabia; Sohag University, Egypt.
    Tahira, Aneela
    University of Sindh, Pakistan.
    Tufail Hussain Sirajuddin; Sherazi, Syed
    University of Sindh, Pakistan.
    Shaikh, Tayyaba
    University of Sindh, Pakistan.
    Arain, Munazza
    University of Sindh, Pakistan.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Hussain Ibupoto, Zafar
    University of Sindh, Pakistan.
    An amperometric sensitive dopamine biosensor based on novel copper oxide nanostructures2017In: Microsystem Technologies: Micro- and Nanosystems Information Storage and Processing Systems, ISSN 0946-7076, E-ISSN 1432-1858, Vol. 23, no 5, p. 1229-1235Article in journal (Refereed)
    Abstract [en]

    It is highly important to explore the influence of counter anions on the morphology in order to have a desired nanostructure with unique properties. Therefore, in this research work the influence of counter anions on the morphology of copper oxide (CuO) nanostructures is presented using copper chloride and copper acetate salts. A significant role of counter anions on the morphology of CuO nanostructures is observed. The hydrothermal method is used to carry out the synthesis of CuO nanomaterial. The prepared CuO nanostructures are characterized by scanning electron microscopy and X-ray diffraction techniques. The prepared CuO nanomaterial exhibits porous nature with thin nanowires and sponge like morphologies. The dopamine sensing application was carried for exploring the electrocatalytic properties of CuO nanostructures. The presented dopamine biosensor exhibited wide linear range for detection of dopamine from 5 to 40 A mu M with sensitivity of 12.8 A mu A mM(-1) cm(-2). The limit of detection and limit of quantification were estimated in order 0.11 and 0.38 A mu M respectively. The developed dopamine biosensor is highly sensitive, selective, stable and reproducible. The common interfering species such as glucose, ascorbic acid and uric acid showed negligible change in the current when same concentration of dopamine and these interfering species was used. The fabricated biosensor could be used for the determination of dopamine from real blood samples.

  • 80.
    Baloach, Qurrat-ul-Ain
    et al.
    University of Sindh, Pakistan.
    Tahira, Aneela
    University of Sindh, Pakistan.
    Begum Mallah, Arfana
    University of Sindh, Pakistan.
    Ishaq Abro, Muhammad
    Mehran University of Engn and Technology, Pakistan.
    Uddin, Siraj
    University of Sindh, Pakistan.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Hussain Ibupoto, Zafar
    University of Sindh, Pakistan.
    A Robust, Enzyme-Free Glucose Sensor Based on Lysine-Assisted CuO Nanostructures2016In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 16, no 11, article id 1878Article in journal (Refereed)
    Abstract [en]

    The production of a nanomaterial with enhanced and desirable electrocatalytic properties is of prime importance, and the commercialization of devices containing these materials is a challenging task. In this study, unique cupric oxide (CuO) nanostructures were synthesized using lysine as a soft template for the evolution of morphology via a rapid and boiled hydrothermal method. The morphology and structure of the synthesized CuO nanomaterial were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The prepared CuO nanostructures showed high potential for use in the electrocatalytic oxidation of glucose in an alkaline medium. The proposed enzyme-free glucose sensor demonstrated a robust response to glucose with a wide linear range and high sensitivity, selectivity, stability, and reproducibility. To explore its practical feasibility, the glucose content of serum samples was successfully determined using the enzyme-free sensor. An analytical recovery method was used to measure the actual glucose from the serum samples, and the results were satisfactory. Moreover, the presented glucose sensor has high chemical stability and can be reused for repetitive measurements. This study introduces an enzyme-free glucose sensor as an alternative tool for clinical glucose quantification.

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  • 81.
    Bandla, Atchaiah
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Highly Linear 2.45 GHz Low-Noise Amplifier Design2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    One critical component of the communication receiver of front-end system is the low-noise amplifier (LNA). For good sensitivity and dynamic range, the LNA should provide a low noise figure and maximum attainable power gain. Another concern is the linearity of the LNA. Strong signals produce intermodulation products in a frequency band close to the operating frequency that might affect the performance of the receiver. In many cases, the intermodulation products can be reduced by increasing the current through the active device. Hence, a trade-off between power consumption and linearity must be considered when designing the LNA. The thesis includes the bias network design, stability analysis, matching network design and layout design of the LNA RF module with layout simulation. The simulation has been performed using Advanced Design System (ADS) simulation software. After implementation of LNA on a PCB, the LNA is measured with the help of the power supply unit and vector network analyzer. The proposed design aim is to provide a low noise figure (NF) and high gain while maintaining the low power consumption.

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  • 82. Order onlineBuy this publication >>
    Bano, Nargis
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Fabrication and Characterization of ZnO Nanorods Based Intrinsic White Light Emitting Diodes (LEDs)2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    ZnO material based hetero-junctions are a potential candidate for the design andrealization of intrinsic white light emitting devices (WLEDs) due to several advantages overthe nitride based material system. During the last few years the lack of a reliable andreproducible p-type doping in ZnO material with sufficiently high conductivity and carrierconcentration has initiated an alternative approach to grow n-ZnO nanorods (NRs) on other ptypeinorganic and organic substrates. This thesis deals with ZnO NRs-hetero-junctions basedintrinsic WLEDs grown on p-SiC, n-SiC and p-type polymers. The NRs were grown by thelow temperature aqueous chemical growth (ACG) and the high temperature vapor liquid solid(VLS) method. The structural, electrical and optical properties of these WLEDs wereinvestigated and analyzed by means of scanning electron microscope (SEM), current voltage(I-V), photoluminescence (PL), cathodoluminescence (CL), electroluminescence (EL) anddeep level transient spectroscopy (DLTS). Room temperature (RT) PL spectra of ZnOtypically exhibit one sharp UV peak and possibly one or two broad deep level emissions(DLE) due to deep level defects in the bandgap. For obtaining detailed information about thephysical origin, growth dependence of optically active defects and their spatial distribution,especially to study the re-absorption of the UV in hetero-junction WLEDs structure depthresolved CL spectroscopy, is performed. At room temperature the CL intensity of the DLEband is increased with the increase of the electron beam penetration depth due to the increaseof the defect concentration at the ZnO NRs/substrate interface. The intensity ratio of the DLEto the UV emission, which is very useful in exploring the origin of the deep level emissionand the distribution of the recombination centers, is monitored. It was found that the deepcenters are distributed exponentially along the ZnO NRs and that there are more deep defectsat the root of ZnO NRs compared to the upper part. The RT-EL spectra of WLEDs illustrateemission band covering the whole visible range from 420 nm and up to 800 nm. The whitelightcomponents are distinguished using a Gaussian function and the components were foundto be violet, blue, green, orange and red emission lines. The origin of these emission lines wasfurther identified. Color coordinates measurement of the WLEDs reveals that the emitted lighthas a white impression. The color rendering index (CRI) and the correlated color temperature(CCT) of the fabricated WLEDs were calculated to be 80-92 and 3300-4200 K, respectively.

    List of papers
    1. Study of Radiative Defects Using Current-Voltage Characteristics in ZnO Rods Catalytically Grown on 4H-p-SiC
    Open this publication in new window or tab >>Study of Radiative Defects Using Current-Voltage Characteristics in ZnO Rods Catalytically Grown on 4H-p-SiC
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    2010 (English)In: Journal of Nanomaterials, Vol. 2010, no 817201Article in journal (Refereed) Published
    Abstract [en]

    High-quality ZnO rods were grown by the vapour-liquid-solid (VLS) technique on 4H-p-SiC substrate. The current transport mechanisms of the diodes at room temperature (RT) have been explained in term of the space-charge-limited current model based on the energy band diagram of ZnO rods/4H-p-SiC heterostructure. The tunneling mechanism via deep-level states was found to be the main conduction process at low-applied voltage but at trap-filled limit voltage VTFL all traps are filled and the space-charge-limited current conduction dominated the current transport. From the RT current voltage measurements, the energy of the deep level trap and the trap concentration were obtained as ∼0.24±0.02 eV and 4.4×1018cm−3, respectively. The deep level states observed correspond to zinc interstitial (Zni ), responsible for the violet emission.

    Place, publisher, year, edition, pages
    Hindawi, 2010
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-67326 (URN)10.1155/2010/817201 (DOI)
    Note
    Original Publication: Nargis Bano, I. Hussain, Omer Nur, Magnus Willander and P. Klason, Study of Radiative Defects Using Current-Voltage Characteristics in ZnO Rods Catalytically Grown on 4H-p-SiC, 2010, Journal of Nanomaterials, (2010), 817201. http://dx.doi.org/10.1155/2010/817201 Licensee: Hindawi Publishing Corporation http://www.hindawi.com/ Available from: 2011-04-08 Created: 2011-04-08 Last updated: 2014-01-15
    2. Study of luminescent centers in ZnO nanorods catalytically grown on 4H-p-SiC
    Open this publication in new window or tab >>Study of luminescent centers in ZnO nanorods catalytically grown on 4H-p-SiC
    Show others...
    2009 (English)In: Semiconductor Science and Technology, ISSN 0268-1242, E-ISSN 1361-6641, Vol. 24, no 12, p. 125015-Article in journal (Refereed) Published
    Abstract [en]

    High-quality ZnO nanorods (NRs) were grown by the vapor-liquid-solid (VLS) technique on 4H-p-SiC substrates. Heterojunction light emitting diodes (LEDs) were fabricated. Electrical characterization including deep level transient spectroscopy (DLTS) complemented by photoluminescence (PL) is used to characterize the heterojunction LEDs. In contrast to previously published results on n-ZnO thin films on p-SiC, we found that the dominant emission is originating from the ZnO NRs. Three luminescence lines have been observed; these are associated with blue (465 nm) and violet (446 nm) emission lines from ZnO NRs emitted by direct transition/recombination of carriers from the conduction band to a zinc vacancy (V-Zn) radiative center and from a zinc interstitial (Zn-i) radiative center to the valance band. The third green-yellow (575 nm) spectral line is emitted due to a transition of carriers from Zn-i to V-Zn. The superposition of these lines led to the observation of strong white light which appears as a wide band in the room temperature PL.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-52416 (URN)10.1088/0268-1242/24/12/125015 (DOI)
    Note
    Original Publication: Nargis Bano, I Hussain, Omer Nour, Magnus Willander, P Klason and Anne Henry, Study of luminescent centers in ZnO nanorods catalytically grown on 4H-p-SiC, 2009, SEMICONDUCTOR SCIENCE AND TECHNOLOGY, (24), 12, 125015. http://dx.doi.org/10.1088/0268-1242/24/12/125015 Copyright: Iop Publishing Ltd http://www.iop.org/ Available from: 2010-01-11 Created: 2009-12-18 Last updated: 2017-12-12Bibliographically approved
    3. Depth-resolved cathodoluminescence study of zinc oxide nanorods catalytically grown on p-type 4H-SiC
    Open this publication in new window or tab >>Depth-resolved cathodoluminescence study of zinc oxide nanorods catalytically grown on p-type 4H-SiC
    Show others...
    2010 (English)In: Journal of Luminescence, ISSN 0022-2313, E-ISSN 1872-7883, Vol. 130, no 6, p. 963-968Article in journal (Refereed) Published
    Abstract [en]

    Optical properties of ZnO nanorods (NRs) grown by vapour-liquid-solid (VLS) technique on 4H-p-SiC substrates were probed by cathodoluminescence (CL) measurements at room temperature and at 5 K complemented with electroluminescence. At room temperature the CL spectra for defect related emission intensity was enhanced with the electron beam penetration depth. We observed a variation in defect related green emission along the nanorod axis. This indicates a relatively poor structural quality near the interface between ZnO NRs and p-SiC substrate. We associate the green emission with oxygen vacancies. Analysis of the low-temperature (5 K) emission spectra in the UV region suggests that the synthesized nanorods contain shallow donors and acceptors.

    Place, publisher, year, edition, pages
    Elsevier Science B.V., Amsterdam., 2010
    Keywords
    ZnO nanorods, Cathodoluminescence, Deep level luminescence
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-56299 (URN)10.1016/j.jlumin.2010.01.006 (DOI)000276916300008 ()
    Note
    Original Publication: Nargis Bano, I Hussain, Omer Nour, Magnus Willander, Qamar Ul Wahab, Anne Henry, H S Kwack, D Le Si Dang, Depth-resolved cathodoluminescence study of zinc oxide nanorods catalytically grown on p-type 4H-SiC, 2010, JOURNAL OF LUMINESCENCE, (130), 6, 963-968. http://dx.doi.org/10.1016/j.jlumin.2010.01.006 Copyright: Elsevier Science B.V., Amsterdam. http://www.elsevier.com/ Available from: 2010-05-07 Created: 2010-05-07 Last updated: 2017-12-12Bibliographically approved
    4. Study of Au/ZnO nanorods Schottky light-emitting diodes grown by low-temperature aqueous chemical method
    Open this publication in new window or tab >>Study of Au/ZnO nanorods Schottky light-emitting diodes grown by low-temperature aqueous chemical method
    Show others...
    2010 (English)In: Applied Physics A: Materials Science & Processing, ISSN 0947-8396, E-ISSN 1432-0630, Vol. 100, no 2, p. 467-472Article in journal (Refereed) Published
    Abstract [en]

    High quality vertically aligned ZnO nanorods (NRs) were grown by low-temperature aqueous chemical technique on 4H-n-SiC substrates. Schottky light-emitting diodes (LEDs) were fabricated. The current-voltage (I-V) characteristics of Schottky diodes reveal good rectifying behavior. Optical properties of the ZnO nanorods (NRs) were probed by cathodoluminescence (CL) measurements at room temperature complemented with electroluminescence (EL). The room-temperature CL spectra of the ZnO NRs exhibit near band edge (NBE) emission as well as strong deep level emission (DLE) centered at 690 nm. At room temperature the CL spectra intensity of the DLE was enhanced with the increase of the electron beam penetration depth due to the increase of defect concentration at the interface and due to the conversion of self-absorbed UV emission. We observed a variation in the DLE along the nanorod depth. This indicates a relatively lower structural quality near the interface between ZnO NRs and n-SiC substrate. The room-temperature CL spectra of SiC show very weak emission, which confirms that most of the DLE is originating from the ZnO NRs, and SiC has a minute contribution to the emission.

    Place, publisher, year, edition, pages
    Springer Science Business Media, 2010
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-58660 (URN)10.1007/s00339-010-5722-0 (DOI)000280556600024 ()
    Available from: 2010-08-22 Created: 2010-08-20 Last updated: 2017-12-12Bibliographically approved
    5. ZnO-organic hybrid white light emitting diodes grown on flexible plastic using low temperature aqueous chemical method
    Open this publication in new window or tab >>ZnO-organic hybrid white light emitting diodes grown on flexible plastic using low temperature aqueous chemical method
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    2010 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 108, no 4, p. 043103-Article in journal (Refereed) Published
    Abstract [en]

    We demonstrate white light luminescence from ZnO-organic hybrid light emitting diodes grown at 90 degrees C on flexible plastic substrate by aqueous chemical growth. The configuration used for the ZnO-organic hybrid white light emitting diodes (WLEDs) consists of a layer of poly (9, 9-dioctylfluorene) (PFO) on poly (3, 4-ethylenedioxythiophene) poly (styrenesulfonate) coated plastic with top ZnO nanorods. Structural, electrical, and optical properties of these WLEDs were measured and analyzed. Room temperature electroluminescence spectrum reveals a broad emission band covering the range from 420 to 750 nm. In order to distinguish the white light components and contribution of the PFO layer we used a Gaussian function to simulate the experimental data. Color coordinates measurement of the WLED reveals that the emitted light has a white impression. The color rendering index and correlated color temperature of the WLED were calculated to be 68 and 5800 K, respectively.

    Place, publisher, year, edition, pages
    American Institute of Physics, 2010
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-60234 (URN)10.1063/1.3475473 (DOI)000281857100016 ()
    Note
    Original Publication: Nargis Bano, Siama Zaman, A Zainelabdin, S Hussain, I Hussain, Omer Nour and Magnus Willander, ZnO-organic hybrid white light emitting diodes grown on flexible plastic using low temperature aqueous chemical method, 2010, JOURNAL OF APPLIED PHYSICS, (108), 4, 043103. http://dx.doi.org/10.1063/1.3475473 Copyright: American Institute of Physics http://www.aip.org/ Available from: 2010-10-08 Created: 2010-10-08 Last updated: 2017-12-12Bibliographically approved
    6. Study of intrinsic white light emission and its components from ZnO-nanorods/p-polymer hybrid junctions grown on glass substrates
    Open this publication in new window or tab >>Study of intrinsic white light emission and its components from ZnO-nanorods/p-polymer hybrid junctions grown on glass substrates
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    2011 (English)In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 46, no 23, p. 7437-7442Article in journal (Refereed) Published
    Abstract [en]

    We report white-light luminescence from ZnO-organic hybrid light emitting diodes grown on glass substrate by low temperature aqueous chemical growth. The configuration used for the hybrid white light emitting diodes (HWLEDs) consists of two-layers of polymers (PEDOT:PSS/PFO) on glass with top ZnO nanorods. Electroluminescence spectra of the HWLEDs demonstrate the combination of emission bands arising from the radiative recombination in polymer and ZnO nanorods. In order to distinguish emission bands we used a Gaussian function to simulate the experimental data. The emitted white light was found to be the superposition of a blue line at 454 nm, a green emission at 540 nm, orange line at 617 nm, and finally a red emission at 680 nm. The transitions causing these emissions are identified and discussed in terms of the energy band diagram of the hybrid junction. Color coordinates measurement of the WLED reveals that the emitted light has a white impression with 70 color rendering index and correlated color temperature 5500 K. Comparison between ITO and aluminum top contacts and its influence on the emitted intensity is also discussed.

    Place, publisher, year, edition, pages
    Springer Verlag (Germany), 2011
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-71543 (URN)10.1007/s10853-011-5708-0 (DOI)000295179700011 ()
    Available from: 2011-10-21 Created: 2011-10-21 Last updated: 2017-12-08Bibliographically approved
    7. Study of the Distribution of Radiative Defects and Reabsorption of the UV in ZnO Nanorods-Organic Hybrid White Light Emitting Diodes (LEDs)
    Open this publication in new window or tab >>Study of the Distribution of Radiative Defects and Reabsorption of the UV in ZnO Nanorods-Organic Hybrid White Light Emitting Diodes (LEDs)
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    2011 (English)In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 4, no 7, p. 1260-1270Article in journal (Refereed) Published
    Abstract [en]

    In this study, the low temperature aqueous chemical growth (ACG) method was employed to synthesized ZnO nanorods to process-organic hybrid white light emitting diodes (LEDs) on glass substrate. Electroluminescence spectra of the hybrid white LEDs demonstrate the combination of emission bands arising from radiative recombination of the organic and ZnO nanorods (NRs). Depth resolved luminescence was used for probing the nature and spatial distribution of radiative defects, especially to study the re-absorption of ultraviolet (UV) in this hybrid white LEDs structure. At room temperature the cathodoluminescence (CL) spectra intensity of the deep band emission (DBE) is increased with the increase of the electron beam penetration depth due to the increase of defect concentration at the ZnO NRs/Polyfluorene (PFO) interface and probably due to internal absorption of the UV. A strong dependency between the intensity ratio of the UV to the DBE bands and the spatial distribution of the radiative defects in ZnO NRs has been found. The comparison of the CL spectra from the PFO and the ZnO NRs demonstrate that PFO has a very weak violet-blue emission band, which confirms that most of the white emission components originate from the ZnO NRs.

    Place, publisher, year, edition, pages
    Basel, Switzerland: MDPI, 2011
    Keywords
    ZnO, yousuf soomro, LEDs
    National Category
    Condensed Matter Physics
    Identifiers
    urn:nbn:se:liu:diva-69643 (URN)10.3390/ma4071260 (DOI)000298245500006 ()
    Projects
    ZnO semiconductor
    Available from: 2011-08-12 Created: 2011-07-08 Last updated: 2017-12-11Bibliographically approved
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    Fabrication and Characterization of ZnO Nanorods Based Intrinsic White Light Emitting Diodes (LEDs)
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    omslag
  • 83.
    Bao, Qinye
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Fabiano, Simone
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Andersson, Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Braun, Slawomir
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Sun, Zhengyi
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Energy Level Bending in Ultrathin Polymer Layers Obtained through Langmuir-Shafer Deposition2016In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 26, no 7, p. 1077-1084Article in journal (Refereed)
    Abstract [en]

    The semiconductor-electrode interface impacts the function and the performance of (opto) electronic devices. For printed organic electronics the electrode surface is not atomically clean leading to weakly interacting interfaces. As a result, solution-processed organic ultrathin films on electrodes typically form islands due to dewetting. It has therefore been utterly difficult to achieve homogenous ultrathin conjugated polymer films. This has made the investigation of the correct energetics of the conjugated polymer-electrode interface impossible. Also, this has hampered the development of devices including ultrathin conjugated polymer layers. Here, LangmuirShafer-manufactured homogenous mono-and multilayers of semiconducting polymers on metal electrodes are reported and the energy level bending using photoelectron spectroscopy is tracked. The amorphous films display an abrupt energy level bending that does not extend beyond the first monolayer. These findings provide new insights of the energetics of the polymer-electrode interface and opens up for new high-performing devices based on ultrathin semiconducting polymers.

    Download full text (pdf)
    fulltext
  • 84.
    Bao, Qinye
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Fabiano, Simone
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Andersson, Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Braun, Slawomir
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Sun, Zhengyi
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    The energetics of the semiconducting polymer-electrode interface for solution-processed electronicsManuscript (preprint) (Other academic)
    Abstract [en]

    The semiconductor-electrode interface impacts the function and the performance of (opto-)electronic devices. For printed organic electronics the electrode surface is not atomically clean leading to weakly interacting interfaces. As a result, solution-processed organic ultra-thin films on electrodes typically form islands due to de-wetting. It has therefore been utterly difficult to achieve homogenous ultrathin conjugated polymer films. This has made the investigation of the correct energetics of the conjugated polymer-electrode interface impossible. Also, this has hampered the development of devices including ultra-thin conjugated polymer layers. Here, we report Langmuir-Shäfer-manufactured homogenous mono- and multilayers of semiconducting polymers on metal electrodes and track the energy level bending using photoelectron spectroscopy. The amorphous films display an abrupt energy level bending that does not extend beyond the first monolayer. Our findings provide new insights of the energetics of the polymer-electrode interface and opens up for new high-performing devices based on ultra-thin semiconducting polymers.

  • 85.
    Baranzahi, Amir
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Lloyd Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Glavmo, M
    Mecel AB, Åmål, Sweden; AB Volvo Technol Dev, Gothenburg, Sweden.
    Carlsson, C
    Mecel AB, Åmål, Sweden; AB Volvo Technol Dev, Gothenburg, Sweden.
    Nytomt, J
    Mecel AB, Åmål, Sweden; AB Volvo Technol Dev, Gothenburg, Sweden.
    Salomonsson, P
    Mecel AB, Åmål, Sweden; AB Volvo Technol Dev, Gothenburg, Sweden.
    Jobson, E
    Mecel AB, Åmål, Sweden; AB Volvo Technol Dev, Gothenburg, Sweden.
    Haggendal, B
    Mecel AB, Åmål, Sweden; AB Volvo Technol Dev, Gothenburg, Sweden.
    Martensson, P
    Mecel AB, Åmål, Sweden; AB Volvo Technol Dev, Gothenburg, Sweden.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Response of metal-oxide-silicon carbide sensors to simulated and real exhaust gases1997In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 43, no 1-3, p. 52-59Article in journal (Refereed)
    Abstract [en]

    Field effect devices based on catalytic metal-oxide-silicon carbide (MOSiC) structures can be used as high temperature gas sensors. The devices are sensitive to hydrocarbons and hydrogen and can be operated up to at least 900 degrees C, which make them suitable for several combustion applications, Simulated and real exhaust gases from a car engine have been studied at sensor temperatures from 200 to 650 degrees C, and it was round that the sensor signal is high for excess hydrocarbon and low for excess oxygen. The response time is less than 100 ms and only a small degradation of the devices was observed after several days of operation. The devices also react to changes of the gas composition In the fuel-rich and fuel-lean region. The devices show an interesting temperature dependence in the fuel rich region.

  • 86.
    Bashir, Fayyaz
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Design and Characterization of Dual Polarized feed for Satellite Communication Antenna2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    So far, extensive research has been made, and researchers have shown that use of septum polarizer for feed designing not only provides the dual polarization but also improve the input reflection and cross-polar isolation performance of the feed.

    In this thesis design of the feed for satellite communication antenna has been investigated, which provides the transmission in right hand circular polarization and reception in left hand circular polarization. A feed which covers both receives and transmits bands, i.e. (7.25-7.75 GHz) and (7.9-8.4 GHz) was designed by using the low axial ratio stepped septum polarizer in square waveguide technology, and the circular horn with the round ring choke at the aperture of the feed. Choke at the aperture of the feed was reduced the level of side and back lobes and improves the gain and efficiency of the reflector antenna by putting more energy at the aperture of the reflector antenna. The excitation of the feed has been done by using the standard WR-112 rectangular waveguide at the input of the feed.

    Design and optimization of the feed have been done in High frequency structure simulator (HFSS) tool, and the simulation results show the input reflection performance of the feed less than -18 dB and the cross-polar isolation better than 25 dB. Finally, the optimized design of feed has been fabricated and measured results show that feed has reasonable input reflection and good cross-polar isolation performance over the entire bandwidth.

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    fulltext
  • 87.
    Batool, S S
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Imran, Z
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology. Pakistan Inst. Engn. and Appl Sci, Pakistan.
    Israr Qadir, Muhammad
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Jamil Rana, Sadaf
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Usman, M
    Pakistan Institute Engn and Appl Science, Pakistan .
    Jamil, H
    Pakistan Institute Engn and Appl Science, Pakistan .
    Rafiq, M A
    Pakistan Institute Engn and Appl Science, Pakistan .
    Hasan, M M
    Pakistan Institute Engn and Appl Science, Pakistan .
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Silica nanofibers based impedance type humidity detector prepared on glass substrate2013In: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 87, p. 1-6Article in journal (Refereed)
    Abstract [en]

    Impedance type relative humidity detector is fabricated by depositing electrospun silica nanofibers on glass substrate. The silica nanofibers with an average diameter similar to 150 nm and length similar to 100 mu m were used. Thermogravimetric and differential scanning calorimetric analysis confirm that the accurate annealing temperature is 500 degrees C for complete removal of PVP. Humidity detecting devices were fabricated by defining titanium electrodes on top of the silica nanofibers. The performance of silica nanofibers humidity detectors was tested by AC electrical measurements at 40-90% relative humidity. The response and the recovery times were 5 s and 3 s, respectively, between 40% and 90% relative humidity. Contribution of dipoles, space charge polarization, relaxation of these dipoles and low frequency dispersion phenomenon were observed during impedance measurements.

  • 88.
    Batool, S S.
    et al.
    Pakistan Institute Engn and Appl Science, Pakistan .
    Imran, Z
    Pakistan Institute Engn and Appl Science, Pakistan .
    Israr Qadir, Muhammad
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Usman, M
    Pakistan Institute Engn and Appl Science, Pakistan .
    Jamil, H
    Pakistan Institute Engn and Appl Science, Pakistan .
    Rafiq, M A.
    Pakistan Institute Engn and Appl Science, Pakistan .
    Hassan, M M.
    Pakistan Institute Engn and Appl Science, Pakistan .
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Comparative Analysis of Ti, Ni, and Au Electrodes on Characteristics of TiO2 Nanofibers for Humidity Sensor Application2013In: Journal of Materials Science & Technology, ISSN 1005-0302, Vol. 29, no 5, p. 411-414Article in journal (Refereed)<