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  • 1.
    Abbas, Khizra
    et al.
    KTH Royal Institute of Technology, Sweden.
    Nee, Hans-Peter
    KTH Royal Institute of Technology, Sweden.
    Kostov, Konstantin Stoychev
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Autonomously Modulating Gate Drivers For Triangular-Current Mode (TCM) Zero-Voltage Switching (ZVS) Buck Converter2023In: Proceedings of 22nd International Symposium on Power Electronics, Ee 2023, Institute of Electrical and Electronics Engineers Inc. , 2023Conference paper (Refereed)
    Abstract [en]

    This paper introduces a novel approach to designing autonomous gate drivers for soft-switched buck converters. The objective is to reduce switching losses, enhance converter efficiency, and reduce electromagnetic interference (EMI). The uniqueness of this converter is that the pulse-width modulation is performed autonomously on the gate driver. The gate driver makes quick decisions on switching times, capitalizing on the minimal time delay between measurements and switching. In the proposed buck converter configuration, the gate driver senses both the current and voltage across the switches to avoid delay. When a slightly negative voltage is detected across the switch, it rapidly turns on, resulting in a zero-voltage switching (ZVS). With an external snubber capacitor placed across the switches, the turn-off switching losses are zero (ZVS). Hence, both the turn-on and turn-off of the switch are soft. To enable the switch to turn off, a reference value of the switch current needs to be sent out to the gate driver using a galvanically isolated current sensor. Through this approach, the efficiency of the 7 kW buck converter has been calculated to exceed 99% without including the filter losses. Additional benefits include reduced switch stresses, diminished electromagnetic interference (EMI), and simplified thermal management.

  • 2.
    Ahlgren, Bengt
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems.
    Claesson, Åsa
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Honfi, Daniel
    RISE Research Institutes of Sweden. Ramböll, Sweden.
    Kardeby, Victor
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems.
    Karoumi, Raid
    KTH Royal Institute of Technology, Sweden.
    Leander, John
    KTH Royal Institute of Technology, Sweden.
    Digitaliseringens möjligheter och utmaningar inom förvaltning och underhållsplanering av broar: Förstudie2020Report (Other academic)
    Abstract [en]

    Rapporten behandlar digitalisering – att införa ny digital teknik – i förvaltningsverksamheten av broar. Omfattningen är en förstudie med syftet att identifiera behovet av framtida forskning för en långsiktig utveckling av broförvaltningen. En grundläggande ansats var att en digitalisering ska minska behovet av kostsamma underhållsåtgärder men bibehålla en hög säkerhet för våra broar. Projektets mål var att samla information om digitala informationsmodeller som skapas under investeringsskedet, utvärdera överlämningen av digitala modeller till förvaltningsskedet, och värdera den eventuella nyttan med digital informationsinsamling för tillståndsbedömning och underhållsplanering. En viktig del av detta var beskrivningen av dagens förvaltningssystem och hur det skulle kunna utvecklas. Studierna har bedrivits genom en enkätundersökning med respondenter från konsultfirmor aktiva inom broprojektering, intervjuer med tekniska experter och litteratursökningar. Resultatet visar att projekteringen av broar idag huvudsakligen görs genom byggnads-informationsmodellering (BIM). Inriktningen är mot byggskedet där samordning och kommunikation bedöms vara de största nyttorna. Överlämningen till förvaltningen består dock av relationsritningar i formen av enkla ritningsfiler. Trots att Trafikverkets strategi för BIM beskriver att en informationsmodell bör leva kvar under hela brons livslängd, finns det tveksamheter huruvida en modell från projekteringen är lämplig som förvaltningsmodell. Istället lyfts andra metoder fram för att skapa en modell av det byggda utförandet. Till exempel optiska metoder för skanning och fotogrammetri. Förvaltningssystemen bör utvecklas med funktioner för att lagra och tillgängliggöra stora mängder digital information från sensorer maskinella inspektioner. Syftet är att minska osäkerheterna i det byggda utförandet och graden av nedbrytning, för att slutligen skapa ett bättre underlag för beslut om åtgärder. Ett framtida scenario är en digital tvilling som speglar den verkliga konstruktionen och uppdateras kontinuerligt genom sensordata. Gällande hårdvara för mätningar behöver sensorer och system utvecklas med avseende på energiförbrukning, energiskördning och underhållsåtgärder, t.ex. genom kombinationer av utbytbara komponenter med kort livslängd och andra delar med lång livslängd. Fiberoptiska sensorer visar på lovande egenskaper men utveckling behövs för att göra dem mer kostnadseffektiva i relation till konventionella sensorer.

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  • 3.
    Akbari, Saeed
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Holmberg, Jonas
    RISE Research Institutes of Sweden, Materials and Production, Manufacturing Processes.
    Andersson, Dag
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Mishra, Madhav
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Brinkfeldt, Klas
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Packaging Induced Stresses in Embedded and Molded GaN Power Electronics Components2023In: Int. Conf. Therm., Mech. Multi-Phys. Simul. Exp. Microelectron. Microsyst., EuroSimE, Institute of Electrical and Electronics Engineers Inc. , 2023Conference paper (Refereed)
    Abstract [en]

    Residual stresses created during the packaging process can adversely affect the reliability of electronics components. We used incremental hole-drilling method, following the ASTM E 837-20 standard, to measure packaging induced residual stresses in discrete packages of power electronics components. For this purpose, we bonded a strain gauge on the surface of a Gallium Nitride (GaN) power component, drilled a hole through the thickness of the component in several incremental steps, recorded the relaxed strain data on the sample surface using the strain gauge, and finally calculated the residual stresses from the measured strain data. The recorded strains and the residual stresses are related by the compliance coefficients. For the hole drilling method in the isotropic materials, the compliance coefficients are calculated from the analytical solutions, and available in the ASTM standard. But for the orthotropic multilayered components typically found in microelectronics assemblies, numerical solutions are necessary. We developed a subroutine in ANSYS APDL to calculate the compliance coefficients of the hole drilling test in the molded and embedded power electronics components. This can extend the capability of the hole drilling method to determine residual stresses in more complex layered structures found in electronics. 

  • 4.
    Akbari, Saeed
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Johansson, Jan
    RISE Research Institutes of Sweden, Materials and Production, Manufacturing Processes.
    Johansson, Emil
    Adaxis, France.
    Tönnäng, Lenny
    RISE Research Institutes of Sweden, Materials and Production, Manufacturing Processes.
    Hosseini, Seyed
    RISE Research Institutes of Sweden, Materials and Production, Manufacturing Processes.
    Large-Scale Robot-Based Polymer and Composite Additive Manufacturing: Failure Modes and Thermal Simulation2022In: Polymers, E-ISSN 2073-4360, Vol. 14, no 9, article id 1731Article in journal (Refereed)
    Abstract [en]

    Additive manufacturing (AM) of large-scale polymer and composite parts using robotic arms integrated with extruders has received significant attention in recent years. Despite the contributions of great technical progress and material development towards optimizing this manufacturing method, different failure modes observed in the final printed products have hindered its application in producing large engineering structures used in aerospace and automotive industries. We report failure modes in a variety of printed polymer and composite parts, including fuel tanks and car bumpers. Delamination and warpage observed in these parts originate mostly from thermal gradients and residual stresses accumulated during material deposition and cooling. Because printing large structures requires expensive resources, process simulation to recognize the possible failure modes can significantly lower the manufacturing cost. In this regard, accurate prediction of temperature distribution using thermal simulations is the first step. Finite element analysis (FEA) was used for process simulation of large-scale robotic AM. The important steps of the simulation are presented, and the challenges related to the modeling are recognized and discussed in detail. The numerical results showed reasonable agreement with the temperature data measured by an infrared camera. While in small-scale extrusion AM, the cooling time to the glassy state is less than 1 s, in large-scale AM, the cooling time is around two orders of magnitudes longer. © 2022 by the authors

  • 5.
    Akbari, Saeed
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Kostov, Konstantin Stoychev
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Brinkfeldt, Klas
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Adolfsson, Erik
    RISE Research Institutes of Sweden, Materials and Production, Manufacturing Processes.
    Lim, Jang-Kwon
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Andersson, Dag
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Bakowski, Mietek
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Wang, Qin
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Salter, Michael
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Ceramic Additive Manufacturing Potential for Power Electronics Packaging2022In: IEEE Transactions on Components, Packaging, and Manufacturing Technology, ISSN 2156-3950, E-ISSN 2156-3985, Vol. 12, no 11, p. 1857-1866Article in journal (Refereed)
    Abstract [en]

    Compared with silicon-based power devices, wide band gap (WBG) semiconductor devices operate at significantly higher power densities required in applications such as electric vehicles and more electric airplanes. This necessitates development of power electronics packages with enhanced thermal characteristics that fulfil the electrical insulation requirements. The present research investigates the feasibility of using ceramic additive manufacturing (AM), also known as three-dimensional (3D) printing, to address thermal and electrical requirements in packaging gallium nitride (GaN) based high-electron-mobility transistors (HEMTs). The goal is to exploit design freedom and manufacturing flexibility provided by ceramic AM to fabricate power device packages with a lower junction-to-ambient thermal resistance (<italic>R</italic>&#x03B8;JA). Ceramic AM also enables incorporation of intricate 3D features into the package structure in order to control the isolation distance between the package source and drain contact pads. Moreover, AM allows to fabricate different parts of the packaging assembly as a single structure to avoid high thermal resistance interfaces. For example, the ceramic package and the ceramic heatsink can be printed as a single part without any bonding layer. Thermal simulations under different thermal loading and cooling conditions show the improvement of thermal performance of the package fabricated by ceramic AM. If assisted by an efficient cooling strategy, the proposed package has the potential to reduce <italic>R</italic>&#x03B8;JA by up to 48%. The results of the preliminary efforts to fabricate the ceramic package by AM are presented, and the challenges that have to be overcome for further development of this manufacturing method are recognized and discussed. 

  • 6.
    Akbari, Saeed
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Kostov, Konstantin Stoychev
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Brinkfeldt, Klas
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Bakowski, Mietek
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Andersson, Dag
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Low Inductive SiC Power Electronics Module with Flexible PCB Interconnections and 3D Printed Casing2022In: 2022 IMAPS Nordic Conference on Microelectronics Packaging, NordPac 2022, Institute of Electrical and Electronics Engineers Inc. , 2022Conference paper (Refereed)
    Abstract [en]

    Silicon carbide (SiC) power devices are steadily increasing their market share in various power electronics applications. However, they require low-inductive packaging in order to realize their full potential. In this research, low-inductive layouts for half-bridge power modules, using a direct bonded copper (DBC) substrate, that are suitable for SiC power devices, were designed and tested. To reduce the negative effects of the switching transients on the gate voltage, flexible printed circuit boards (PCBs) were used to interconnect the gate and source pins of the module with the corresponding pads of the power chips. In addition, conductive springs were used as low inductive, solder-free contacts for the module power terminals. The module casing and lid were produced using additive manufacturing, also known as 3D printing, to create a compact design. It is shown that the inductance of this module is significantly lower than the commercially available modules.

  • 7.
    Akbari, Saeed
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Sakhaei, A. H.
    University of Kent, UK.
    Panjwani, S.
    Singapore University of Technology and Design, Singapore.
    Kowsari, K.
    Singapore University of Technology and Design, Singapore.
    Ge, Q.
    Southern University of Science and Technology, China.
    Shape memory alloy based 3D printed composite actuators with variable stiffness and large reversible deformation2021In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 321, article id 112598Article in journal (Refereed)
    Abstract [en]

    Soft composite actuators can be fabricated by embedding shape memory alloy (SMA) wires into soft polymer matrices. Shape retention and recovery of these actuators are typically achieved by incorporating shape memory polymer segments into the actuator structure. However, this requires complex manufacturing processes. This work uses multimaterial 3D printing to fabricate composite actuators with variable stiffness capable of shape retention and recovery. The hinges of the bending actuators presented here are printed from a soft elastomeric layer as well as a rigid shape memory polymer (SMP) layer. The SMA wires are embedded eccentrically over the entire length of the printed structure to provide the actuation bending force, while the resistive wires are embedded into the SMP layer of the hinges to change the temperature and the bending stiffness of the actuator hinges via Joule heating. The temperature of the embedded SMA wire and the printed SMP segments is changed sequentially to accomplish a large bending deformation, retention of the deformed shape, and recovery of the original shape, without applying any external mechanical force. The SMP layer thickness was varied to investigate its effect on shape retention and recovery. A nonlinear finite element model was used to predict the deformation of the actuators. 

  • 8.
    Akbari, Saeed
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Sakhaei, A. H.
    University of Kent, UK.
    Panjwani, S.
    Singapore University of Technology and Design, Singapore.
    Kowsari, K.
    Singapore University of Technology and Design, Singapore.
    Ge, Q.
    Singapore University of Technology and Design, Singapore; Southern University of Science and Technology, China.
    Shape-reversible 4D printing aided by shape memory alloys2022In: Smart Materials in Additive Manufacturing, volume 2: 4D Printing Mechanics, Modeling, and Advanced Engineering Applications, Elsevier , 2022, p. 387-406Chapter in book (Other academic)
    Abstract [en]

    Four-dimensional (4D) printed structures fabricated from shape memory polymers (SMPs) are typically one-way actuators, that is, for each actuation cycle, they must be programmed to deform from the original (as-printed) shape to a secondary (programmed) shape. This is done by applying a combination of thermal and mechanical loads. Then, they restore the initial shape during the actuation process by applying a thermal load. Here, we generalize this concept to fabricate two-way actuators by embedding shape memory alloy (SMA) wires into the printed SMP structures. To explain this in greater detail, we describe the printing process of a two-way bending actuator whose bilayer hinges consist of stiff SMPs as well as elastomers with low modulus. Joule heating was employed to modulate the hinges bending stiffness. To this end, electrical current was applied to the resistive wires inserted into the hinges SMP layer to control their temperature. On the other hand, thermomechanical programming of the SMA wires, which were integrated into the actuator, provided the bending actuation force. The fabricated actuator was able to bend, maintain the deformed shape, and recover the as-fabricated shape in a fully automated manner. Further potentials of this design methodology were assessed using a nonlinear finite element model. The model incorporated user-defined subroutines to incorporate complex material behaviors of SMAs and SMPs. 

  • 9.
    Amorebieta, Josu
    et al.
    University of the Basque Country, Spain.
    Pereira, Joao
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Durana, Gaizka
    University of the Basque Country, Spain.
    Franciscangelis, Carolina
    RISE Research Institutes of Sweden.
    Ortega-Gomez, Angel
    University of the Basque Country, Spain.
    Zubia, Joseba
    University of the Basque Country, Spain.
    Villatoro, Joel
    University of the Basque Country, Spain; Ikerbasque-Basque Foundation for Science, Spain.
    Margulis, Walter
    RISE Research Institutes of Sweden.
    Twin-core fiber sensor integrated in laser cavity2022In: Scientific Reports, E-ISSN 2045-2322, Vol. 12, no 1, article id 11797Article in journal (Refereed)
    Abstract [en]

    In this work, we report on a twin-core fiber sensor system that provides improved spectral efficiency, allows for multiplexing and gives low level of crosstalk. Pieces of the referred strongly coupled multicore fiber are used as sensors in a laser cavity incorporating a pulsed semiconductor optical amplifier (SOA). Each sensor has its unique cavity length and can be addressed individually by electrically matching the periodic gating of the SOA to the sensor’s cavity roundtrip time. The interrogator acts as a laser and provides a narrow spectrum with high signal-to-noise ratio. Furthermore, it allows distinguishing the response of individual sensors even in the case of overlapping spectra. Potentially, the number of interrogated sensors can be increased significantly, which is an appealing feature for multipoint sensing. © 2022, The Author(s).

  • 10.
    Andersson Ersman, Peter
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Boda, Ulrika
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Petsagkourakis, Ioannis
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Åhlin, Jessica
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Posset, Uwe
    Fraunhofer, Germany.
    Schott, Marco
    Fraunhofer, Germany.
    Brooke, Robert
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Reflective and Complementary Transmissive All-Printed Electrochromic Displays Based on Prussian Blue2023In: Advanced Engineering Materials, ISSN 1438-1656, E-ISSN 1527-2648, Vol. 25, no 6, article id 2201299Article in journal (Refereed)
    Abstract [en]

    By combining the electrochromic (EC) properties of Prussian blue (PB) and poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), complementary EC displays manufactured by slot-die coating and screen printing on flexible plastic substrates are reported. Various display designs have been realized, resulting in displays operating in either transmissive or reflective mode. For the transmission mode displays, the color contrast is enhanced by the complementary switching of the two EC electrodes PB and PEDOT:PSS. Both electrodes are either exhibiting a concurrent colorless or blue appearance. For the displays operating in reflection mode, a white opaque electrolyte is used in conjunction with the EC properties of PB, resulting in a display device switching between a fully white state and a blue-colored state. The developments of the different device architectures, that either operate in reflection or transmission mode, demonstrate a scalable manufacturing approach of all-printed EC displays that may be used in a large variety of Internet of Things applications. © 2022 The Authors. 

  • 11.
    Andersson Ersman, Peter
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Eriksson, Jerry
    RISE Research Institutes of Sweden, Built Environment, Building and Real Estate. Elitfönster AB, Sweden.
    Jakonis, Darius
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Pantzare, Sandra
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Åhlin, Jessica
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Strandberg, Jan
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Sundin, Stefan
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Toss, Henrik
    RISE Research Institutes of Sweden, Digital Systems, Mobility and Systems.
    Ahrentorp, Fredrik
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Daoud, Kaies
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Jonasson, Christian
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Svensson, Henrik
    Elitfönster AB, Sweden.
    Gregard, Greger
    ChromoGenics AB, Sweden.
    Näslund, Ulf
    Vasakronan AB, Sweden.
    Johansson, Christer
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Integration of Screen Printed Piezoelectric Sensors for Force Impact Sensing in Smart Multifunctional Glass Applications2022In: Advanced Engineering Materials, ISSN 1438-1656, E-ISSN 1527-2648, Vol. 24, no 11, article id 2200399Article in journal (Refereed)
    Abstract [en]

    Screen printed piezoelectric polyvinylidene fluoride?trifluoro ethylene (PVDF?TrFE)-based sensors laminated between glass panes in the temperature range 80?110?°C are presented. No degradation of the piezoelectric signals is observed for the sensors laminated at 110?°C, despite approaching the Curie temperature of the piezoelectric material. The piezoelectric sensors, here monitoring force impact in smart glass applications, are characterized by using a calibrated impact hammer system and standardized impact situations. Stand-alone piezoelectric sensors and piezoelectric sensors integrated on poly(methyl methacrylate) are also evaluated. The piezoelectric constants obtained from the measurements of the nonintegrated piezoelectric sensors are in good agreement with the literature. The piezoelectric sensor response is measured by using either physical electrical contacts between the piezoelectric sensors and the readout electronics, or wirelessly via both noncontact capacitive coupling and Bluetooth low-energy radio link. The developed sensor concept is finally demonstrated in smart window prototypes, in which integrated piezoelectric sensors are used to detect break-in attempts. Additionally, each prototype includes an electrochromic film to control the light transmittance of the window, a screen printed electrochromic display for status indications and wireless communication with an external server, and a holistic approach of hybrid printed electronic systems targeting smart multifunctional glass applications.

  • 12.
    Andersson Ersman, Peter
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Freitag, Kathrin
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Kawahara, Jun
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware. Lintec Corporation, Japan.
    Åhlin, Jessica
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    The rise of electrochromics through dynamic QR codes and grayscale images in screen printed passive matrix addressed displays2022In: Scientific Reports, E-ISSN 2045-2322, Vol. 12, no 1, article id 10959Article in journal (Refereed)
    Abstract [en]

    Electronic matrix addressed displays capable of presenting arbitrary grayscale images typically require complex device architectures including switching components to provide unique pixel addressability. Here, we demonstrate high-yield manufacturing of passive matrix addressed electrochromic displays on flexible substrates by solely using screen printing. The simple pixel architecture, obtained by printing only three active layers on top of each other, concurrently provides both the electrochromic functionality and the critical non-linear pixel switching response that enables presentation of arbitrary grayscale images in the resulting passive matrix addressed displays. The all-printed display technology exhibits unprecedented performance and is further verified by dynamic QR codes, to exemplify utilization within authentication, packaging, or other emerging Internet of Things applications requiring a low-cost display for data visualization. © 2022, The Author(s).

  • 13.
    Andersson Ersman, Peter
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Freitag, Kathrin
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Nilsson, Marie
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Åhlin, Jessica
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Brooke, Robert
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Nordgren, Niklas
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Aulin, Christian
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Fall, Andreas
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Nevo, Yuval
    Melodea Ltd, Israel.
    Beni, Valerio
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Electrochromic Displays Screen Printed on Transparent Nanocellulose-Based Substrates2023In: Advanced Photonics Research, ISSN 2699-9293, article id 2200012Article in journal (Refereed)
    Abstract [en]

    Manufacturing of electronic devices via printing techniques is often considered to be an environmentally friendly approach, partially due to the efficient utilization of materials. Traditionally, printed electronic components (e.g., sensors, transistors, and displays) are relying on flexible substrates based on plastic materials; this is especially true in electronic display applications where, most of the times, a transparent carrier is required in order to enable presentation of the display content. However, plastic-based substrates are often ruled out in end user scenarios striving toward sustainability. Paper substrates based on ordinary cellulose fibers can potentially replace plastic substrates, but the opaqueness limits the range of applications where they can be used. Herein, electrochromic displays that are manufactured, via screen printing, directly on state-of-the-art fully transparent substrates based on nanocellulose are presented. Several different nanocellulose-based substrates, based on either nanofibrillated or nanocrystalline cellulose, are manufactured and evaluated as substrates for the manufacturing of electrochromic displays, and the optical and electrical switching performances of the resulting display devices are reported and compared. The reported devices do not require the use of metals and/or transparent conductive oxides, thereby providing a sustainable all-printed electrochromic display technology.

  • 14.
    Andersson Ersman, Peter
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Lassnig, Roman
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Strandberg, Jan
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Dyreklev, Peter
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Flexible Active Matrix Addressed Displays Manufactured by Screen Printing2020In: Advanced Engineering Materials, ISSN 1438-1656, E-ISSN 1527-2648, Vol. 23, article id 2000771Article in journal (Refereed)
    Abstract [en]

    A flexible, electrochromic, active matrix addressed display (AMAD) is demonstrated. The monolithically integrated AMAD, which contains a 3 × 3 array of organic electrochromic smart pixels (OESPs), is manufactured on a plastic substrate solely using screen printing. Each OESP is based on the combination of one organic electrochromic display (OECD) and one organic electrochemical transistor (OECT), where both devices are screen printed into multilayered vertical architectures. The conduction state of the OECT enables control of the color state of its corresponding OECD, thereby circumventing cross-talk effects in the resulting AMAD device. The manufacturing approach also involves electrical wires, which connect each OECD with its corresponding OECT and also serve as the addressing lines of the resulting AMAD device, that are formed by screen printing of an ink based on either silver or nanocopper.

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  • 15.
    Andersson Ersman, Peter
    et al.
    RISE Research Institutes of Sweden, Digital Systems.
    Zabihipour, Marzieh
    Linköping University, Sweden.
    Tu, Deyu
    Linköping University, Sweden.
    Lassnig, Roman
    RISE Research Institutes of Sweden, Digital Systems.
    Strandberg, Jan
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Åhlin, Jessica
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Nilsson, Marie
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Westerberg, David
    RISE Research Institutes of Sweden, Digital Systems.
    Gustafsson, Göran
    RISE Research Institutes of Sweden, Digital Systems.
    Berggren, Magnus
    Linköping University, Sweden.
    Forchheimer, Robert
    Linköping University, Sweden.
    Fabiano, Simone
    Linköping University, Sweden.
    Monolithic integration of display driver circuits and displays manufactured by screen printing2020In: Flexible and Printed Electronics, ISSN 2058-8585, Vol. 5, no 2, article id 024001Article in journal (Refereed)
    Abstract [en]

    Here, we report all-screen printed display driver circuits, based on organic electrochemical transistors (OECTs), and their monolithic integration with organic electrochromic displays (OECDs). Both OECTs and OECDs operate at low voltages and have similar device architectures, and, notably, they rely on the very same electroactive material as well as on the same electrochemical switching mechanism. This then allows us to manufacture OECT-OECD circuits in a concurrent manufacturing process entirely based on screen printing methods. By taking advantage of the high current throughput capability of OECTs, we further demonstrate their ability to control the light emission in traditional light-emitting diodes (LEDs), where the actual LED addressing is achieved by an OECT-based decoder circuit. The possibility to monolithically integrate all-screen printed OECTs and OECDs on flexible plastic foils paves the way for distributed smart sensor labels and similar Internet of Things applications.

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  • 16.
    Andersson Ersman, Peter
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Åhlin, Jessica
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Westerberg, David
    RISE Research Institutes of Sweden.
    Sawatdee, Anurak
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Arvén, Patrik
    J2 Holding AB, Sweden.
    Ludvigsson, Mikael
    RISE Research Institutes of Sweden, Built Environment, Building and Real Estate.
    Batteryless Electronic System Printed on Glass Substrate2021In: Electronic Materials, E-ISSN 2673-3978, Vol. 2, no 4Article in journal (Refereed)
    Abstract [en]

    Batteryless hybrid printed electronic systems manufactured on glass substrates are reported. The electronic system contains a sensor capable of detecting water, an electrochromic display, conductors, a silicon chip providing the power supply through energy harvesting of electromagnetic radiation, and a silicon-based microcontroller responsible for monitoring the sensor status and the subsequent update of the corresponding display segment. The silicon-based components were assembled on the glass substrate by using a pick and place equipment, while the remainder of the system was manufactured by screen printing. Many printed electronic components, often relying on organic materials, are sensitive to variations in environmental conditions, and the reported system paves the way for the creation of electronic sensor platforms on glass substrates for utilization in see-through applications in harsh conditions. Additionally, this generic hybrid printed electronic sensor system also demonstrates the ability to enable autonomous operation through energy harvesting in future smart window applications.

  • 17.
    Andersson, S. A.
    et al.
    University of Gothenburg, Sweden; Sahlgrenska University Hospital, Sweden.
    Danielsson, A.
    University of Gothenburg, Sweden.
    Ohlsson, F
    RISE Research Institutes of Sweden. Umeå University, Sweden.
    Wipenmyr, Jan
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Alt Murphy, M.
    University of Gothenburg, Sweden; Sahlgrenska University Hospital, Sweden.
    Arm impairment and walking speed explain real-life activity of the affected Arm and leg after stroke2021In: Journal of Rehabilitation Medicine, ISSN 1650-1977, E-ISSN 1651-2081, Vol. 53, no 6, article id jrm00210Article in journal (Refereed)
    Abstract [en]

    Objective: To determine to what extent accelerometer-based arm, leg and trunk activity is associated with sensorimotor impairments, walking capacity and other factors in subacute stroke. Design: Cross-sectional study. Patients: Twenty-six individuals with stroke (mean age 55.4 years, severe to mild motor impairment). Methods: Data on daytime activity were collected over a period of 4 days from accelerometers placed on the wrists, ankles and trunk. A forward stepwise linear regression was used to determine associations between free-living activity, clinical and demographic variables. Results: Arm motor impairment (Fugl-Meyer Assessment) and walking speed explained more than 60% of the variance in daytime activity of the more-affected arm, while walking speed alone explained 60% of the more-affected leg activity. Activity of the less-affected arm and leg was associated with arm motor impairment (R2=0.40) and independence in walking (R2=0.59). Arm activity ratio was associated with arm impairment (R2=0.63) and leg activity ratio with leg impairment (R2=0.38) and walking speed (R2=0.27). Walking-related variables explained approximately 30% of the variance in trunk activity. Conclusion: Accelerometer-based free-living activity is dependent on motor impairment and walking capacity. The most relevant activity data were obtained from more-affected limbs. Motor impairment and walking speed can provide some information about real-life daytime activity levels.

  • 18.
    Armgarth, Astrid
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware. Linköping University, Sweden.
    Pantzare, Sandra
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Arven, Patrik
    J2 Holding AB, Sweden.
    Lassnig, Roman
    RISE Research Institutes of Sweden.
    Jinno, Hiroaki
    RIKEN Center for Emergent Matter Science, Japan; University of Tokyo, Japan.
    Gabrielsson, Erik
    Linköping University, Sweden.
    Kifle, Yonatan
    Linköping University, Sweden.
    Cherian, Dennis
    Linköping University, Sweden.
    Arbring Sjöström, Theresia
    Linköping University, Sweden.
    Berthou, Gautier
    RISE Research Institutes of Sweden.
    Dowling, Jim
    RISE Research Institutes of Sweden, Digital Systems, Data Science. KTH Royal Institute of Technology, Sweden.
    Someya, Takao
    RIKEN Center for Emergent Matter Science, Japan; University of Tokyo, Japan.
    Wikner, Jacob
    Linköping University, Sweden.
    Gustafsson, Göran
    RISE Research Institutes of Sweden.
    Simon, Daniel
    Linköping University, Sweden.
    Berggren, Magnus
    Linköping University, Sweden.
    A digital nervous system aiming toward personalized IoT healthcare2021In: Scientific Reports, E-ISSN 2045-2322, Vol. 11, no 1, article id 7757Article in journal (Refereed)
    Abstract [en]

    Body area networks (BANs), cloud computing, and machine learning are platforms that can potentially enable advanced healthcare outside the hospital. By applying distributed sensors and drug delivery devices on/in our body and connecting to such communication and decision-making technology, a system for remote diagnostics and therapy is achieved with additional autoregulation capabilities. Challenges with such autarchic on-body healthcare schemes relate to integrity and safety, and interfacing and transduction of electronic signals into biochemical signals, and vice versa. Here, we report a BAN, comprising flexible on-body organic bioelectronic sensors and actuators utilizing two parallel pathways for communication and decision-making. Data, recorded from strain sensors detecting body motion, are both securely transferred to the cloud for machine learning and improved decision-making, and sent through the body using a secure body-coupled communication protocol to auto-actuate delivery of neurotransmitters, all within seconds. We conclude that both highly stable and accurate sensing—from multiple sensors—are needed to enable robust decision making and limit the frequency of retraining. The holistic platform resembles the self-regulatory properties of the nervous system, i.e., the ability to sense, communicate, decide, and react accordingly, thus operating as a digital nervous system. © 2021, The Author(s).

  • 19.
    Bai, Xiaohong
    et al.
    Northwest University, China; Carleton University, Canada.
    Claesson, Åsa
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Laronche, Albane
    Carleton University, Canada.
    Liu, Fu
    Carleton University, Canada.
    Hu, Manli
    Northwest University, China.
    Albert, Jaques
    Carleton University, Canada.
    Sensing applications of fiber Bragg gratings in single mode fibers with as-drawn 25 μm diameter cladding2021In: Optics and Laser Technology, ISSN 0030-3992, E-ISSN 1879-2545, Vol. 144, article id 107451Article in journal (Refereed)
    Abstract [en]

    The sensing properties of fiber Bragg gratings (FBG) inscribed in single mode fiber with a 5 μm diameter core and 25 μm diameter cladding are studied experimentally for temperature, strain, bending, and surrounding refractive index. Compared to normal single mode fiber, the diameter of this fiber is 5 times smaller and it stretches 14.5 times more at the same applied load. Therefore, it is much more flexible and stretchable, while maintaining excellent optical quality at wavelengths near 1550 nm. In addition to a core mode back reflection resonance, strong FBGs inscribed in this fiber show a relatively small number of narrow bandwidth (0.7 nm) cladding mode resonances separated in wavelength by 2.5–6 nm. This relatively coarse spectral comb can then be used to sense many different kinds of perturbations involving core and cladding modes. In particular, unlike cladding-mode based sensors made from tilted FBGs, all resonances are of the same azimuthal order as the core mode (i.e. HE1m). This feature makes these gratings particularly sensitive to bending which causes the appearance of new resonances and reduced amplitudes of the original ones, each by up to 10 dB/mm−1 of curvature. On the other hand, the temperature sensitivities of all modes are similar to that of standard fiber (around 11 pm/oC) while strain sensitivities are somewhat higher (1.6–1.7 pm/μstrain). The surrounding refractive index sensitivity is also increased (by a factor of 3) over normal fiber, mostly due to the increased modal dispersion of the modes of the thinner cladding. Furthermore, it is possible to serially multiplex different gratings at different wavelengths by interleaving their resonance combs and preserving each grating identity in the combined spectrum.

  • 20.
    Bakowski, Mietek
    et al.
    RISE, Swedish ICT, Acreo. RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Lim, J-K
    RISE, Swedish ICT, Acreo.
    Kaplan, W
    Merits of Buried Grid Technology for SiC JBS Diodes2012In: ECS Transactions, ISSN 1938-5862, E-ISSN 1938-6737, Vol. 50, no 3, p. 415-424Article in journal (Refereed)
  • 21.
    Bamgbopa, M. O.
    et al.
    Linköping University, Sweden; Dubai Electricity and Water Authority, United Arab Emirates.
    Belaineh, D.
    Linköping University, Sweden.
    Mengistie, D. A.
    Linköping University, Sweden; California Polytechnic State University, USA.
    Edberg, Jesper
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Engquist, I.
    Linköping University, Sweden.
    Berggren, M.
    Linköping University, Sweden.
    Tybrandt, K.
    Linköping University, Sweden.
    Modelling of heterogeneous ion transport in conducting polymer supercapacitors2021In: Journal of Materials Chemistry A, ISSN 2050-7488, E-ISSN 2050-7496, Vol. 9, no 4, p. 2184-2194Article in journal (Refereed)
    Abstract [en]

    The ongoing electrification of many energy systems has created a large demand for low-cost and scalable electrical energy storage solutions. Conducting polymer supercapacitors have received significant attention for this purpose due to the abundance of their constituent materials. Although there exists a large body of experimental work on conducting polymer supercapacitors, a detailed understanding of the mixed electronic-ionic transport processes within these devices and the included materials, is still lacking. Modelling, in combination with experimental data, is a powerful tool to facilitate a detailed understanding of the transport processes within the materials and devices. However, to date, there has been a shortage of physical models which account for the non-ideal capacitances typically found in conducting polymer-based supercapacitors. Here, we report a novel model which reproduces experimental data and provides insights into the cyclic voltammograms, galvanostatic charge-discharge curves, self-discharge characteristics, and impedance spectroscopy results of supercapacitors based on the conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) and cellulose nanofibrils. We find that the non-ideal capacitive characteristics of the supercapacitors can be reproduced by the incorporation of heterogeneous ion transport features within the electrodes, comprising low ion diffusivity regions. The difference in charging rates of the high and low ion diffusivity regions accounts for the experimentally observed trends in cyclic voltammograms and self-discharge characteristics. The developed model demonstrates how complex transport processes, which govern the specifications of organic energy devices, can be analysed beyond the scope of conventional equivalent circuit models. It also provides an insight into how various transport and polarization processes are manifested in real measurement data and thus defines the limiting processes of conducting polymer energy storage devices.

  • 22.
    Belaineh Yilma, Dagmawi
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Brooke, Robert
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Sani, Negar
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Say, Mehmet
    Linköping University, Sweden.
    Håkansson, Karl MO
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Engquist, Isak
    Linköping University, Sweden.
    Berggren, Magnus
    Linköping University, Sweden.
    Edberg, Jesper
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Printable carbon-based supercapacitors reinforced with cellulose and conductive polymers2022In: Journal of Energy Storage, ISSN 2352-152X, E-ISSN 2352-1538, Vol. 50, article id 104224Article in journal (Refereed)
    Abstract [en]

    Sustainable electrical energy storage is one of the most important scientific endeavors of this century. Battery and supercapacitor technologies are here crucial, but typically the current state of the art suffers from either lack of large-scale production possibilities, sustainability or insufficient performance and hence cannot match growing demands in society. Paper and cellulosic materials are mature scalable templates for industrial roll-to-roll production. Organic materials, such as conducting polymers, and carbon derivatives are materials that can be synthesized or derived from abundant sources. Here, we report the combination of cellulose, PEDOT:PSS and carbon derivatives for bulk supercapacitor electrodes adapted for printed electronics. Cellulose provides a mesoscopic mesh for the organization of the active ingredients. Furthermore, the PEDOT:PSS in combination with carbon provides superior device characteristics when comparing to the previously standard combination of activated carbon and carbon black. PEDOT:PSS acts as a mixed ion-electron conducting glue, which physically binds activated carbon particles together, while at the same time facilitating swift transport of both electrons and ions. A surprisingly small amount (10%) of PEDOT:PSS is needed to achieve an optimal performance. This work shows that cellulose added to PEDOT:PSS-carbon enables high-performing, mechanically stable, printed supercapacitor electrodes using a combination of printing methods.

  • 23.
    Bhadoria, Shubhangi
    et al.
    KTH Royal Institute of Technology, Sweden.
    Dijkhuizen, Frans
    KTH Royal Institute of Technology, Sweden; Hitachi Energy Research, Sweden.
    Raj, Rishabh
    KTH Royal Institute of Technology, Sweden.
    Wang, Xiongfei
    KTH Royal Institute of Technology, Sweden.
    Xu, Qianwen
    KTH Royal Institute of Technology, Sweden.
    Matioli, Elison
    EPFL Institute of Electrical Engineering, Switzerland.
    Kostov, Konstantin Stoychev
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Nee, Hans-Peter
    KTH Royal Institute of Technology, Sweden.
    Enablers for Overcurrent Capability of Silicon-Carbide-Based Power Converters: An Overview2023In: IEEE transactions on power electronics, ISSN 0885-8993, E-ISSN 1941-0107, Vol. 38, no 3, p. 3569-3589Article in journal (Refereed)
    Abstract [en]

    With the increase in penetration of power electronic converters in the power systems, a demand for overcurrent/ overloading capability has risen for the fault clearance duration. This article gives an overview of the limiting factors and the recent technologies for the overcurrent performance of SiC power modules in power electronics converters. It presents the limitations produced at the power module level by packaging materials, which include semiconductor chips, substrates, metallization, bonding techniques, die attach, and encapsulation materials. Specifically, technologies for overcurrent related temperatures in excess of 200°C are discussed. This article also discusses potential technologies, which have been proven or may be potential candidates for improving the safe operating area. The discussed technologies are use of phase-change materials below the semiconductor chip, Peltier elements, new layouts of the power modules, control and modulation techniques for converters. Special attention has been given to an overview of various potential phase-change materials, which can be considered for high-temperature operations. 

  • 24.
    Bjurström, Johan
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware. Chalmers University of Technology, Sweden.
    Ohlsson, Fredrik
    RISE Research Institutes of Sweden. Umeå University, Sweden.
    Rusu, Cristina
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Johansson, Christer
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware. Chalmers University of Technology, Sweden.
    Unified Modeling and Analysis of Vibration Energy Harvesters under Inertial Loads and Prescribed Displacements2022In: Applied Sciences: APPS, E-ISSN 1454-5101, Vol. 12, no 19Article in journal (Refereed)
    Abstract [en]

    In this paper, we extend the optimization analysis found in the current literature for single-degree-of-freedom vibrational energy harvesters. We numerically derive and analyze the optimization conditions based on unified expressions for piezoelectric and electromagnetic energy harvesters. Our contribution lies in the detailed analysis and comparison of both resonant and anti-resonant states while fully including the effect of intrinsic resistance. We include both the case of excitation by inertial load and prescribed displacement, as the latter has not been elaborated on in the previous literature and provides new insights. We perform a general analysis but also consider typical values of applied piezoelectric and electromagnetic energy harvesters. Our results improve upon previous similar comparative studies by providing new and useful insights regarding optimal load, load power and power input to output efficiency. Our analysis shows an exponential increase in the critical mechanical quality factor due to the resistive loss coefficient. We find that the ratio of mechanical quality factor to resistive loss coefficient, at resonance, increases drastically close to the theoretical maximum for load power. Under the same optimization conditions, an equivalent conclusion can be drawn regarding efficiency. We find that the efficiency at anti-resonance behaves differently and is equal to or larger than the efficiency at resonance. We also show that the optimal load coefficient at resonance has a significant dependence on the mechanical quality factor only when the resistive loss coefficient is large. Our comparison of excitation types supports the previous literature, in a simple and intuitive way, regarding optimal load by impedance matching and power output efficiency. Our modeling and exploration of new parameter spaces provide an improved tool to aid the development of new harvester prototypes.

  • 25.
    Bjurström, Johan
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware. Chalmers University of Technology, Sweden .
    Ohlsson, Fredrik
    RISE Research Institutes of Sweden. Umeå University, Sweden.
    Vikerfors, Andreas
    ReVibe Energy AB, Sweden.
    Rusu, Cristina
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Johansson, Christer
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Tunable spring balanced magnetic energy harvester for low frequencies and small displacements2022In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 259, article id 115568Article in journal (Refereed)
    Abstract [en]

    In this paper we present a novel concept to efficiently harvest vibrational energy at low frequencies and very small displacement. We describe and evaluate an electromagnetic energy harvester which generates power from a magnetic circuit with motion induced variations of an air gap. External vibrations induce oscillations of the gap length around an equilibrium point, due to a linear spring counteracting the magnetic force. The relative position of the spring can be adjusted to optimize the harvester output for excitation amplitude and frequency. A simulation model is built in COMSOL and verified by comparison with lab measurements. The simulation model is used to determine the potential performance of the proposed concept under both harmonic and non-harmonic excitation. Under harmonic excitation, we achieve a simulated RMS load power of 26.5 μW at 22 Hz and 0.028 g acceleration amplitude. From a set of comparable EH we achieve the highest theoretical power metric of 1712.2 µW/cm3/g2 while maintaining the largest relative bandwidth of 81.8%. Using measured non-harmonic vibration data, with a mean acceleration of 0.039 g, resulted in a mean power of 52 μW. Moreover, the simplicity and robustness of our design makes it a competitive alternative for use in practical situations. © 2022 The Author(s)

  • 26.
    Boda, Ulrika
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware. Linköping University, Sweden.
    Petsagkourakis, Ioannis
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Beni, Valerio
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Andersson Ersman, Peter
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Tybrandt, Klas
    Linköping University, Sweden.
    Fully Screen-Printed Stretchable Organic Electrochemical Transistors2023In: Advanced Materials Technologies, E-ISSN 2365-709XArticle in journal (Refereed)
    Abstract [en]

    Stretchable organic electrochemical transistors (OECTs) are promising for wearable applications within biosensing, bio-signal recording, and addressing circuitry. Efficient large-scale fabrication of OECTs can be performed with printing methods but to date there are no reports on high-performance fully printed stretchable OECTs. Herein, this challenge is addressed by developing fully screen-printed stretchable OECTs based on an architecture that minimizes electrochemical side reactions and improves long-term stability. Fabrication of the OECTs is enabled by in-house development of three stretchable functional screen-printing inks and related printing processes. The stretchable OECTs show good characteristics in terms of transfer curves, output characteristics, and transient response up to 100% static strain and 500 strain cycles at 25% and 50% strain. The strain insensitivity of the OECTs can be further improved by strain conditioning, resulting in stable performance up to 50% strain. Finally, an electrochromic smart pixel is demonstrated by connecting a stretchable OECT to a stretchable electrochromic display. It is believed that the development of screen-printed stretchable electrochemical devices, and OECTs in particular, will pave the way for their use in wearable applications and commercial products. © 2023 The Authors. 

  • 27.
    Boda, Ulrika
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware. Linköping University, Sweden.
    Strandberg, Jan
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Eriksson, Jens
    Linköping University, Sweden.
    Liu, Xianjie
    Linköping University, Sweden.
    Beni, Valerio
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Tybrandt, Klas
    Linköping University, Sweden.
    Screen-Printed Corrosion-Resistant and Long-Term Stable Stretchable Electronics Based on AgAu Microflake Conductors2023In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252Article in journal (Refereed)
    Abstract [en]

    High-throughput production methods such as screen printing can bring stretchable electronics out of the lab into the market. Most stretchable conductor inks for screen printing are based on silver nanoparticles or flakes due to their favorable performance-to-cost ratio, but silver is prone to tarnishing and corrosion, thereby limiting the stability of such conductors. Here, we report on a cost-efficient and scalable approach to resolve this issue by developing screen printable inks based on silver flakes chemically coated by a thin layer of gold. The printed stretchable AgAu conductors reach a conductivity of 8500 S cm-1, remain conductive up to 250% strain, show excellent corrosion and tarnishing stability, and are used to demonstrate wearable LED and NFC circuits. The reported approach is attractive for smart clothing, as the long-term functionality of such devices is expected in a variety of environments. © 2023 The Authors.

  • 28.
    Brooke, Robert
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Edberg, Jesper
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Petsagkourakis, Ioannis
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Freitag, Kathrin
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Mulla, Mohammad Yusuf
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Nilsson, Marie
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Isacsson, Patrik
    Linköping University, Sweden; Ahlstrom Group Innovation, France.
    Andersson Ersman, Peter
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Paper Electronics Utilizing Screen Printing and Vapor Phase Polymerization2023In: Advanced Sustainable Systems, ISSN 2366-7486Article in journal (Refereed)
    Abstract [en]

    The rise of paper electronics has been accelerated due to the public push for sustainability. Electronic waste can potentially be avoided if certain materials in electronic components can be substituted for greener alternatives such as paper. Within this report, it is demonstrated that conductive polymers poly(3,4-ethylenedoxythiophene) (PEDOT), polypyrrole, and polythiophene, can be synthesized by screen printing combined with vapor phase polymerization on paper substrates and further incorporated into functional electronic components. High patterning resolution (100 µm) is achieved for all conductive polymers, with PEDOT showing impressive sheet resistance values. PEDOT is incorporated as conductive circuitry and as the active material in all-printed electrochromic displays. The conductive polymer circuits allow for functional light emitting diodes, while the electrochromic displays are comparable to commercial displays utilizing PEDOT on plastic substrates. 

  • 29.
    Brooke, Robert
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Fall, Andreas
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Borras, M.
    LEITAT Technological Center, Spain.
    Belaineh Yilma, Dagmawi
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Edberg, Jesper
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Martinez-Crespiera, S.
    LEITAT Technological Center, Spain.
    Aulin, Christian
    RISE Research Institutes of Sweden, Bioeconomy and Health.
    Beni, Valerio
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Nanocellulose based carbon ink and its application in electrochromic displays and supercapacitors2021In: Flexible and Printed Electronics, ISSN 2058-8585, Vol. 6, no 4, article id 045011Article in journal (Refereed)
    Abstract [en]

    Conventional electronics have been highlighted as a very unsustainable technology; hazardous wastes are produced both during their manufacturing but also, due to their limited recyclability, during their end of life cycle (e.g. disposal in landfill). In recent years additive manufacturing processes (i.e. screen printing) have attracted significant interest as a more sustainable approach to electronic manufacturing (printed electronics). Despite the field of printed electronics addressing some of the issues related to the manufacturing of electronics, many components and inks are still considered hazardous to the environment and are difficult to recycle. Here we present the development of a low environmental impact carbon ink based on a non-hazardous solvent and a cellulosic matrix (nanocellulose) and its implementation in electrochromic displays (ECDs) and supercapacitors. As part of the reported work, a different protocol for mixing carbon and cellulose nanofibrils (rotation mixing and high shear force mixing), nanocellulose of different grades and different carbon: nanocellulose ratios were investigated and optimized. The rheology profiles of the different inks showed good shear thinning properties, demonstrating their suitability for screen-printing technology. The printability of the developed inks was excellent and in line with those of reference commercial carbon inks. Despite the lower electrical conductivity (400 S m-1 for the developed carbon ink compared to 1000 S m-1 for the commercial inks), which may be explained by their difference in composition (carbon content, density and carbon derived nature) compared to the commercial carbon, the developed ink functioned adequately as the counter electrode in all screen-printed ECDs and even allowed for improved supercapacitors compared to those utilizing commercial carbon inks. In this sense, the supercapacitors incorporating the developed carbon ink in the current collector layer had an average capacitance = 97.4 mF cm-2 compared to the commercial carbon ink average capacitance = 61.6 mF cm-2. The ink development reported herein provides a step towards more sustainable printed green electronics. © 2021 The Author(s).

  • 30.
    Brooke, Robert
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Freitag, Kathrin
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Petsagkourakis, Ioannis
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Nilsson, Martin
    Andersson Ersman, Peter
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    All-Printed Electrochromic Stickers2023In: Macromolecular materials and engineering, ISSN 1438-7492, E-ISSN 1439-2054Article in journal (Refereed)
    Abstract [en]

    Displays are one of the most mature technologies in the field of printed electronics. Their ability to be manufactured in large quantities and at low cost has led to their recent uptake into the consumer market. Within this article this technology is extended to electrochromic display stickers. This is achieved using a recent reverse display architecture screen printed on textile and paper sticker substrates. The electrochromic stickers are comparable to plastic control substrates and show little performance difference even when adhered to curved surfaces. The electrochromic display technology is extended to sticker labels for authentication applications by patterning either the dielectric or the graphical layer. A proof-of-concept prototype emulating a wax seal on an envelope is presented to show that other colors can be implemented in this technology. © 2023 The Authors.

  • 31.
    Brooke, Robert
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Lay, M
    Linköping University, Sweden; Leibniz Institute for New Materials, Germany.
    Jain, K
    KTH Royal Institute of Technology, Sweden.
    Francon, H
    KTH Royal Institute of Technology, Sweden.
    Say, Mehmet
    Linköping University, Sweden.
    Belaineh Yilma, Dagmawi
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Wang, Xin
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Håkansson, Karl
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Wågberg, L
    KTH Royal Institute of Technology, Sweden.
    Engquist, I
    Linköping University, Sweden; .
    Edberg, Jesper
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Berggren, M
    Linköping University, Sweden.
    Nanocellulose and PEDOT:PSS composites and their applications2023In: Polymer Reviews, ISSN 1558-3724, no 2, p. 437-Article in journal (Refereed)
    Abstract [en]

    The need for achieving sustainable technologies has encouraged research on renewable and biodegradable materials for novel products that are clean, green, and environmentally friendly. Nanocellulose (NC) has many attractive properties such as high mechanical strength and flexibility, large specific surface area, in addition to possessing good wet stability and resistance to tough chemical environments. NC has also been shown to easily integrate with other materials to form composites. By combining it with conductive and electroactive materials, many of the advantageous properties of NC can be transferred to the resulting composites. Conductive polymers, in particular poly(3,4-ethylenedioxythiophene:poly(styrene sulfonate) (PEDOT:PSS), have been successfully combined with cellulose derivatives where suspensions of NC particles and colloids of PEDOT:PSS are made to interact at a molecular level. Alternatively, different polymerization techniques have been used to coat the cellulose fibrils. When processed in liquid form, the resulting mixture can be used as a conductive ink. This review outlines the preparation of NC/PEDOT:PSS composites and their fabrication in the form of electronic nanopapers, filaments, and conductive aerogels. We also discuss the molecular interaction between NC and PEDOT:PSS and the factors that affect the bonding properties. Finally, we address their potential applications in energy storage and harvesting, sensors, actuators, and bioelectronics. © 2022 The Author(s). 

  • 32.
    Brooke, Robert
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Petsagkourakis, Ioannis
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Majee, Subimal
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Olsson, Oliver
    Chalmers University of Technology, Sweden.
    Dahlin, Aandres
    Chalmers University of Technology, Sweden.
    Andersson Ersman, Peter
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    All-Printed Multilayers and Blends of Poly(dioxythiophene) Derivatives Patterned into Flexible Electrochromic Displays2023In: Macromolecular materials and engineering, ISSN 1438-7492, E-ISSN 1439-2054, Vol. 308, no 2, article id 2200453Article in journal (Refereed)
    Abstract [en]

    Low-cost, flexible and thin display technology is becoming an interesting field of research as it can accompany the wide range of sensors being developed. Here, the synthesis of poly(dimethylpropylene-dioxythiophene) (PProDOT-Me2) by combining vapor phase polymerization and screen printing is presented. A multilayer architecture using poly(3,4-ethylenedioxythiophene) (PEDOT) and PProDOT-Me2 to allow for electrochromic switching of PProDOT-Me2, thereby eliminating the need for a supporting transparent conductive (metal oxide) layer is introduced. Furthermore, the technology is adapted to a blended architecture, which removes the additional processing steps and results in improved color contrast (∆E* &gt; 25). This blend architecture is extended to other conductive polymers, such as PEDOT and polypyrrole (PPy), to highlight the ability of the technique to adjust the color of all-printed electrochromic displays. As a result, a green color is obtained when combining the blue and yellow states of PEDOT and PPy, respectively. This technology has the potential to pave the way for all-printed multicolored electrochromic displays for further utilization in printed electronic systems in various Internet of Things applications. © 2022 The Authors. 

  • 33.
    Brooke, Robert
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Petsagkourakis, Ioannis
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Wijeratne, Kosala
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Andersson Ersman, Peter
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Electrochromic Displays Manufactured by a Combination of Vapor Phase Polymerization and Screen Printing2022In: Advanced Materials Technologies, E-ISSN 2365-709X, Vol. 7, no 8, article id 2200054Article in journal (Refereed)
    Abstract [en]

    Smart label technology such as indicators is a growing field due to society's demand for Internet of Things devices. New materials and technologies are continuously being discovered and developed in order to provide better resolution, better performance, or more environmentally friendly devices. Within this report, screen printing technology is combined with vapor phase polymerization to synthesize three conductive polymers; poly(3,4-ethylenedioxythiophene) (PEDOT), polypyrrole (PPy), and polythiophene (PTh). The conductive polymers are created in micrometer resolution and investigated for their electrochromic properties. PEDOT and PPy samples are combined into printed, laminated, transmissive electrochromic displays. The technology is further advanced to establish separate PEDOT, PPy, and PTh all-printed electrochromic displays using several screen printed layers. The PEDOT displays show improved color retention as compared to displays created with commercially available PEDOT:poly(styrene sulfonate) (PSS) with comparable contrast and switching behavior. All-printed PPy and PTh electrochromic displays with impressive electrochromic behavior are demonstrated. More complex patterns of 7-segment displays are created, thereby highlighting flexibility and individually switched sections of the conductive polymers. This research extends the screen printing and vapor phase polymerization combination to other conductive polymers and the potential commercialization of multicolor electrochromic displays that has been otherwise dominated by monochromatic PEDOT:PSS. 

  • 34.
    Brooke, Robert
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Wijeratne, Kosala
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Hübscher, Kathrin
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Belaineh Yilma, Dagmawi
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Andersson Ersman, Peter
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Combining Vapor Phase Polymerization and Screen Printing for Printed Electronics on Flexible Substrates2022In: Advanced Materials Technologies, E-ISSN 2365-709X, Vol. 7, no 7, article id 2101665Article in journal (Refereed)
    Abstract [en]

    Large area manufacturing of printed electronic components on ~A4-sized substrates is demonstrated by the combination of screen printing and vapor phase polymerization (VPP) into poly(3,4-ethylenedioxythiophene) (PEDOT). The oxidant layer required for the polymerization process is screen printed, and the resulting conductive polymer patterns are manufactured at high resolution (100 µm). Successful processing of several common oxidant species is demonstrated, and the thickness can be adjusted by altering the polymerization time. By comparing the polymer films of this work to a commercial PEDOT:PSS (PEDOT doped with poly(styrene sulfonate)) screen printing ink shows improved surface roughness (26 vs 69 nm), higher conductivity (500 vs 100 S cm–1) and better resolution (100 vs 200 µm). Organic electrochemical transistors, in which the transistor channel is polymerized into PEDOT through VPP, are also demonstrated to further emphasize on the applicability of this manufacturing approach. The resulting transistor devices are not only functional, they also show remarkable switching behavior with respect to ON current levels (–70 mA at –1 V), ON/OFF ratios (&gt;105), switching times (tens of ms) and transconductance values (&gt;100 mS) in standalone transistor devices, in addition to a high amplification factor (&gt;30) upon integration into a screen printed inverter circuit. © 2022 The Authors. 

  • 35.
    Brooke, Robert
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Åhlin, Jessica
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Hübscher, Kathrin
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Hagel, Olle
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Strandberg, Jan
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Sawatdee, Anurak
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Edberg, Jesper
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Large-scale paper supercapacitors on demand2022In: Journal of Energy Storage, ISSN 2352-152X, E-ISSN 2352-1538, Vol. 50, article id 104191Article in journal (Refereed)
    Abstract [en]

    Clean, sustainable electrical energy could be the next greatest challenge and opportunity of mankind. While the creation of clean energy has been proven, the storage of such energy requires much more research and development. Battery and energy storage technology today relies heavily on rare metals which cannot support large production needs of society. Therefore, the need for energy storage technology to be created sustainably is of great importance. Recently, conductive polymers, a class of organic materials, have shown impressive results in energy storage but requires further development if this technology is to be implemented in various energy storage applications. Here, we report a new ‘on demand’ design for supercapacitors that allows for individual devices in addition to devices in parallel and in series to increase the capacitance and voltage, respectively. The individual device showed impressive capacity up to 10 F while increasing the area with the large parallel device increased the capacitance to a record 127.8 F (332.8 mF/cm2). The ‘on demand’ design also allows paper supercapacitors to be in series to increase the operating voltage with an example device showing good charging behavior up to 5 V when 4 individual paper supercapacitors were arranged in series. Finally, the paper supercapacitors were incorporated into a prototype titled: ‘Norrkoping Starry Night’ which bridges the gap between art and science. An all-printed electrochromic display showing the city of Norrkoping, Sweden, complete with a touch sensor as an on/off switch and silicon solar cells to charge the paper supercapacitors is presented to bring several printed technologies together, highlighting the possibilities of the new paper supercapacitors within this report. © 2022

  • 36.
    Burden, Håkan
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Stenberg, Susanne
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Regulating Trust – An Ongoing Analysis of the AI Act2022Report (Other academic)
    Abstract [en]

    The initial proposal for an EU act regulating Artificial Intelligence, commonly referred to as the AI Act, has undergone substantial modifications under the Slovenian, French and Czech presidencies since it’s proposal by the Commission in spring 2021. As the content and details change over time it has become necessary to analyse to what extent the act will build trust towards AI as technology. In this position paper the ambition is to highlight one aspect of the act – the relation to trust – based on the version drafted for the general approach by the Council. Now, even reducing the analysis to one aspect is a complex task and the chosen points are the ones we have seen gaining most interest with the stakeholders we have interacted with. There are other points that could have been included but we have chosen to leave them out so as to not obscure the overall picture by all the details. The text does not follow a traditional structure of Introduction – Method – Results. Rather it represents nuggets we have dug out while exploring the proposed regulation, here analysed in relation to the notion of trust. We also assume that the reader has a basic understanding of the initial proposal. For those interested in a more detailed account of our method we recommend our contribution on agile principles for analysing upcoming regulations. Before we get going, we want to make it clear that while we are indebted to numerous representatives from commercial enterprises, public administrators spanning across EU departments to Swedish municipalities as well as researchers from different institutions, we are solely responsible for the claims and the analysis presented in this contribution.

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  • 37.
    Burger, Paul
    et al.
    Chalmers University of Technology, Sweden; Johannes Gutenberg University Mainz, Germany.
    Singh, G.
    Chalmers University of Technology, Sweden; Institute of Materials Science of Barcelona , Spain.
    Johansson, Christer
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware. Chalmers University of Technology, Sweden.
    Moya, Carlos
    Université Libre de Bruxelles, Belgium.
    Bruylants, Gilles
    Université Libre de Bruxelles, Belgium.
    Jakob, Gerhard
    Johannes Gutenberg University Mainz, Germany.
    Kalaboukhov, Alexei
    Chalmers University of Technology, Sweden.
    Atomic Force Manipulation of Single Magnetic Nanoparticles for Spin-Based Electronics2022In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 16, no 11, p. 19253-19260Article in journal (Refereed)
    Abstract [en]

    Magnetic nanoparticles (MNPs) are instrumental for fabrication of tailored nanomagnetic structures, especially where top-down lithographic patterning is not feasible. Here, we demonstrate precise and controllable manipulation of individual magnetite MNPs using the tip of an atomic force microscope. We verify our approach by placing a single MNP with a diameter of 50 nm on top of a 100 nm Hall bar fabricated in a quasi-two-dimensional electron gas (q2DEG) at the oxide interface between LaAlO3 and SrTiO3 (LAO/STO). A hysteresis loop due to the magnetic hysteresis properties of the magnetite MNPs was observed in the Hall resistance. Further, the effective coercivity of the Hall resistance hysteresis loop could be changed upon field cooling at different angles of the cooling field with respect to the measuring field. The effect is associated with the alignment of the MNP magnetic moment along the easy axis closest to the external field direction across the Verwey transition in magnetite. Our results can facilitate experimental realization of magnetic proximity devices using single MNPs and two-dimensional materials for spin-based nanoelectronics. © 2022 The Authors. 

  • 38.
    Burkhardt, C.
    et al.
    Pforzheim University, Germany.
    van Nielen, S.
    Leiden University, Netherlands.
    Awais, M.
    University of Birmingham, UK.
    Bartolozzi, F.
    B&C Speakers, Italy.
    Blomgren, Jakob
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Ortiz, P.
    Inserma Anoia SL, Spain.
    Xicotencatl, M. B.
    Leiden University, Netherlands.
    Degri, M.
    University of Birmingham, UK.
    Nayebossadri, S.
    University of Birmingham, UK.
    Walton, A.
    University of Birmingham, UK.
    An overview of Hydrogen assisted (Direct) recycling of Rare earth permanent magnets2023In: Journal of Magnetism and Magnetic Materials, ISSN 0304-8853, E-ISSN 1873-4766, Vol. 588, no B, article id 171475Article in journal (Refereed)
    Abstract [en]

    Rare Earths (RE) permanent magnets are essential components for Europe’s successful green and digital transition However, the entire value chain of RE magnetic materials depends on imports, which are highly vulnerable in current global supply chain models. To mitigate this situation, EU Regulation plans that at least 15 % of the EU’s annual consumption of permanent magnets should be covered by recycling capacities by 2030. Researchers in the EU H2020 project SUSMAGPRO consortium have shown that hydrogen can be used as a very efficient recycling method to extract NdFeB magnet powder from various EOL Components in the IP protected Hydrogen-based Processing of Magnet Scrap (HPMS). On exposure to hydrogen the sintered NdFeB magnets break down into a friable, demagnetised, hydrogenated powder containing an interstitial hydride of Nd2Fe14BHX (10 mu m) and smaller particles (<1 <mu>m) from the grain-boundary phase NdH2.7. This process delivers a sustainable source of magnetic material for the production of sintered, polymer bonded and metal-injection moulded magnets. The paper will present numerous results along the whole value chain of magnet recycling, including automatic dismantling of magnet containing products, magnets extraction, HPMS recycling, production of recycled magnets and demonstrator testing. It will also discuss best practices and bottlenecks of the processes as an outlook for successful design-for-recycling of future applications.

  • 39.
    Castillejo, Pedro
    et al.
    Universidad Politecnica de Madrid, Spain.
    Johansen, Gorm
    SINTEF, Norway.
    Cürüklü, Baran
    Mälardalen University, Sweden.
    Bilbao-Arechabala, Sonia
    Tecnalia, Spain.
    Fresco, Roberto
    CNR IMAMOTER, Italy.
    Martínez-Rodríguez, Belen
    Tecnalia, Spain.
    Pomante, Luigi
    Università degli Studi dell'Aquila, Italy.
    Rusu, Cristina
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Martínez-Ortega, Jose
    Universidad Politecnica de Madrid, Spain.
    Centofanti, Carlo
    Università degli Studi dell'Aquila, Italy.
    Hakojärvi, Mikko
    Mtech Digital Solutions Ltd, Finland.
    Santic, Marco
    Università degli Studi dell'Aquila, Italy.
    Häggman, Johanna
    Mtech Digital Solutions Ltd, Finland.
    Aggregate Farming in the Cloud: The AFarCloud ECSEL project2020In: Microprocessors and microsystems, ISSN 0141-9331, E-ISSN 1872-9436, Vol. 78, article id 103218Article in journal (Refereed)
    Abstract [en]

    Farming is facing many economic challenges in terms of productivity and cost-effectiveness. Labor shortage partly due to depopulation of rural areas, especially in Europe, is another challenge. Domain specific problems such as accurate monitoring of soil and crop properties and animal health are key factors for minimizing economical risks, and not risking human health. The ECSEL AFarCloud (Aggregate Farming in the Cloud) project will provide a distributed platform for autonomous farming that will allow the integration and cooperation of agriculture Cyber Physical Systems in real-time in order to increase efficiency, productivity, animal health, food quality and reduce farm labor costs. Moreover, such a platform can be integrated with farm management software to support monitoring and decision-making solutions based on big data and real-time data mining techniques. © 2020 The Author(s)

  • 40.
    Cavallaro, Sara
    et al.
    KTH Royal Institute of Technology, Sweden.
    Hååg, Petra
    Karolinska Institute, Sweden.
    Viktorsson, Kristina
    Karolinska Institute, Sweden.
    Krozer, Anatol
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Fogel, Kristina
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Lewensohn, Rolf
    Karolinska Institute, Sweden; Karolinska University Hospital, Sweden.
    Linnros, Jan
    KTH Royal Institute of Technology, Sweden.
    Dev, Apurba
    KTH Royal Institute of Technology, Sweden; Uppsala University, Sweden.
    Comparison and optimization of nanoscale extracellular vesicle imaging by scanning electron microscopy for accurate size-based profiling and morphological analysis2021In: Nanoscale Advances, E-ISSN 2516-0230, Vol. 3, no 11, p. 3053-3063Article in journal (Refereed)
    Abstract [en]

    Nanosized extracellular vesicles (EVs) have been found to play a key role in intercellular communication, offering opportunities for both disease diagnostics and therapeutics. However, lying below the diffraction limit and also being highly heterogeneous in their size, morphology and abundance, these vesicles pose significant challenges for physical characterization. Here, we present a direct visual approach for their accurate morphological and size-based profiling by using scanning electron microscopy (SEM). To achieve that, we methodically examined various process steps and developed a protocol to improve the throughput, conformity and image quality while preserving the shape of EVs. The study was performed with small EVs (sEVs) isolated from a non-small-cell lung cancer (NSCLC) cell line as well as from human serum, and the results were compared with those obtained from nanoparticle tracking analysis (NTA). While the comparison of the sEV size distributions showed good agreement between the two methods for large sEVs (diameter > 70 nm), the microscopy based approach showed a better capacity for analyses of smaller vesicles, with higher sEV counts compared to NTA. In addition, we demonstrated the possibility of identifying non-EV particles based on size and morphological features. The study also showed process steps that can generate artifacts bearing resemblance with sEVs. The results therefore present a simple way to use a widely available microscopy tool for accurate and high throughput physical characterization of EVs.

  • 41.
    Chen, Hao
    et al.
    Carnegie Mellon University, USA.
    Billington, David
    Cardiff University, UK.
    Riordan, Edward
    Cardiff University, UK.
    Blomgren, Jakob
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Giblin, Sean
    Cardiff University, UK.
    Johansson, Christer
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Majetich, Sara
    Carnegie Mellon University, USA.
    Tuning the dynamics in Fe3O4nanoparticles for hyperthermia optimization2020In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 117, no 7, article id 073702Article in journal (Refereed)
    Abstract [en]

    The AC magnetic susceptibility (ACS) of Fe3O4 nanoparticles was measured between 10 kHz and 4 MHz at different temperatures and in applied DC fields. In this frequency range, magnetostatic interactions impact magnetization dynamics even for dilute assemblies. The ACS spectrum of relaxation frequencies changes both with temperature and the addition of a small DC field. Because both the relaxation peak frequency and amplitude can be tuned with the DC field, these results could be applied to magnetic hyperthermia applications to optimize heat delivery. 

  • 42.
    Chen, Shangzhi
    et al.
    Linköping University, Sweden.
    Petsagkourakis, Ioannis
    Linköping University, Sweden.
    Spampinato, Nicoletta
    University Bordeaux, France.
    Kuang, Chaoyang
    Linköping University, Sweden.
    Liu, Xianjie
    Linköping University, Sweden.
    Brooke, Robert
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Kang, Evan
    Linköping University, Sweden.
    Fahlman, Mats
    Linköping University, Sweden.
    Crispin, Xavier
    Linköping University, Sweden.
    Pavlopoulou, Eleni
    University Bordeaux, France.
    Jonsson, Magnus
    Linköping University, Sweden.
    Unraveling vertical inhomogeneity in vapour phase polymerized PEDOT:Tos films2020In: Journal of Materials Chemistry A, ISSN 2050-7488, E-ISSN 2050-7496, Vol. 8, no 36, p. 18726-18734Article in journal (Refereed)
    Abstract [en]

    The conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) forms a promising alternative to conventional inorganic conductors, where deposition of thin filmsviavapour phase polymerization (VPP) has gained particular interest owing to high electrical conductivity within the plane of the film. The conductivity perpendicular to the film is typically much lower, which may be related not only to preferential alignment of PEDOT crystallites but also to vertical stratification across the film. In this study, we reveal non-linear vertical microstructural variations across VPP PEDOT:Tos thin films, as well as significant differences in doping level between the top and bottom surfaces. The results are consistent with a VPP mechanism based on diffusion-limited transport of polymerization precursors. Conducting polymer films with vertical inhomogeneity may find applications in gradient-index optics, functionally graded thermoelectrics, and optoelectronic devices requiring gradient doping. 

  • 43.
    Chen, Shangzhi
    et al.
    Linköping University, Sweden.
    Rossi, Stefano
    Linköping University, Sweden.
    Shanker, Ravi
    Linköping University, Sweden.
    Cincotti, Giancarlo
    Linköping University, Sweden.
    Gamage, Sampath
    Linköping University, Sweden.
    Kühne, Philipp
    Linköping University, Sweden.
    Stanishev, Vallery
    Linköping University, Sweden.
    Engquist, Isak
    Linköping University, Sweden.
    Berggren, Magnus
    Linköping University, Sweden.
    Edberg, Jesper
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Darakchieva, Vanya
    Linköping University, Sweden.
    Jonsson, Magnus P
    Linköping University, Sweden.
    Tunable Structural Color Images by UV-Patterned Conducting Polymer Nanofilms on Metal Surfaces.2021In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 33, no 33, article id 2102451Article in journal (Refereed)
    Abstract [en]

    Precise manipulation of light-matter interactions has enabled a wide variety of approaches to create bright and vivid structural colors. Techniques utilizing photonic crystals, Fabry-Pérot cavities, plasmonics, or high-refractive-index dielectric metasurfaces have been studied for applications ranging from optical coatings to reflective displays. However, complicated fabrication procedures for sub-wavelength nanostructures, limited active areas, and inherent absence of tunability of these approaches impede their further development toward flexible, large-scale, and switchable devices compatible with facile and cost-effective production. Here, a novel method is presented to generate structural color images based on monochromic conducting polymer films prepared on metallic surfaces via vapor phase polymerization and ultraviolet (UV) light patterning. Varying the UV dose enables synergistic control of both nanoscale film thickness and polymer permittivity, which generates controllable structural colors from violet to red. Together with grayscale photomasks this enables facile fabrication of high-resolution structural color images. Dynamic tuning of colored surfaces and images via electrochemical modulation of the polymer redox state is further demonstrated. The simple structure, facile fabrication, wide color gamut, and dynamic color tuning make this concept competitive for applications like multifunctional displays.

  • 44.
    Claesson, Åsa
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Franciscangelis, Carolina
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Pereira, Joao
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Weldehawariat, Tedros
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Hey Tow, Kenny
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    FBG Applications in 25um Diameter Fibers2022In: Optics InfoBase Conference Papers, Optica Publishing Group (formerly OSA) , 2022Conference paper (Refereed)
    Abstract [en]

    Ultrathin 25μm optical fibers with FBG sensors are manufactured and used as vibration sensors in glass-fiber reinforced composites. The use of ultrathin fibers is discussed, and their manufacture is described. © 2022 The Authors.

  • 45.
    Colaço, Marcos
    et al.
    Rio de Janeiro State University, Brazil.
    Camara, Alexandre
    Rio de Janeiro State University, Brazil.
    Nogueira, Liebert
    University of Oslo, Norway.
    Carvalho, Isabel
    Pontifícia Universidade Católica Do Rio de Janeiro, Brazil.
    Margulis, Walter
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware. KTH Royal Institute of Technologt, Sweden.
    Barroso, Regina
    Rio de Janeiro State University, Brazil.
    Characterization of the microstructures of specialty optical fibers for electric-field sensing by propagation-based x-ray phase-contrast microtomography2021In: Measurement science and technology, ISSN 0957-0233, E-ISSN 1361-6501, Vol. 32, no 6, article id 065401Article in journal (Refereed)
    Abstract [en]

    In this work, we present a quantitative (statistical) 3D morphological characterization of optical fibers used in electric-field sensing. The characterization technique employs propagation-based x-ray phase-contrast microcomputed tomography (micro-CT). In particular, we investigate specialty optical fibers that contain microstructured holes that are electro-optically modified by thermal poling to induce second-order nonlinear effects (SONE). The efficiency of the SONE is reflected in the characterization parameter, Vπ, which is highly dependent on the dimensions of the fiber. The fiber microstructures must be uniform to support the fabrication of reproducible devices. The results obtained using the micro-CT technique show that uncertainty of ±1.7% arises in the determination of the expected value of the voltage that causes a change in the phase of the electromagnetic wave equal to π rad (Vπ ), demonstrating a great advantage, compared with other techniques e.g. SEM, which would need at least 1000 images of the cross-section of an optical fiber, taken at different points, making the process more expensive and time-consuming.

  • 46.
    Dejke, Valter
    et al.
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles.
    Eng, Matthias
    RISE Research Institutes of Sweden.
    Brinkfeldt, Klas
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Charnley, Josephine
    Lusstech, UK.
    Lussey, David
    Lusstech, UK.
    Lussey, Chris
    Lusstech, UK.
    Development of prototype low-cost qtss™ wearable flexible more enviro-friendly pressure, shear, and friction sensors for dynamic prosthetic fit monitoring2021In: Sensors, E-ISSN 1424-8220, Vol. 21, no 11, article id 3764Article in journal (Refereed)
    Abstract [en]

    There is a current healthcare need for improved prosthetic socket fit provision for the masses using low-cost and simple to manufacture sensors that can measure pressure, shear, and friction. There is also a need to address society’s increasing concerns regarding the environmental impact of electronics and IoT devices. Prototype thin, low-cost, and low-weight pressure, shear, and loss of friction sensors have been developed and assembled for trans-femoral amputees. These flexible and conformable sensors are simple to manufacture and utilize more enviro-friendly novel magnetite-based QTSS™ (Quantum Technology Supersensor™) quantum materials. They have undergone some initial tests on flat and curved surfaces in a pilot amputee trial, which are presented in this paper. These initial findings indicate that the prototype pressure sensor strip is capable of measuring pressure both on flat and curved socket surfaces in a pilot amputee trial. They have also demonstrated that the prototype shear sensor can indicate increasing shear forces, the resultant direction of the shear forces, and loss of friction/slippage events. Further testing, amputee trials, and ongoing optimization is continuing as part of the SocketSense project to assist prosthetic comfort and fit. © 2021 by the authors

  • 47.
    Edberg, Jesper
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Boda, Ulrika
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware. Linköping University, Sweden.
    Mulla, Yusuf
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Brooke, Robert
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Pantzare, Sandra
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Strandberg, Jan
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Fall, Andreas
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Economou, Konstantin
    Linköping University, Sweden.
    Beni, Valerio
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Armgarth, Astrid
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    A Paper‐Based Triboelectric Touch Interface: Toward Fully Green and Recyclable Internet of Things2023In: Advanced Sensor Research, Vol. 2, no 1, article id 2200015Article in journal (Refereed)
    Abstract [en]

    The transition to a sustainable society is driving the development of green electronic solutions designed to have a minimal environmental impact. One promising route to achieve this goal is to construct electronics from biobased materials like cellulose, which is carbon neutral, non‐toxic, and recyclable. This is especially true for internet‐of‐things devices, which are rapidly growing in number and are becoming embedded in every aspect of our lives. Here, paper‐based sensor circuits are demonstrated, which use triboelectric pressure sensors to help elderly people communicate with the digital world using an interface in the form of an electronic “book”, which is more intuitive to them. The sensors are manufactured by screen printing onto flexible paper substrates, using in‐house developed cellulose‐based inks with non‐hazardous solvents. The triboelectric sensor signal, generated by the contact between a finger and chemically modified cellulose, can reach several volts, which can be registered by a portable microcontroller card and transmitted by Bluetooth to any device with an internet connection. Apart from the microcontroller (which can be easily removed), the whole system can be recycled at the end of life. A triboelectric touch interface, manufactured using printed electronics on flexible paper substrates, using cellulose‐based functional inks is demonstrated. These metal‐free green electronics circuits are implemented in an “electronic book” demonstrator, equipped with wireless communication that can control remote devices, as a step toward sustainable and recyclable internet‐of‐things devices.

  • 48.
    Edberg, Jesper
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Brooke, Robert
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Hosseinaei, Omid
    RISE Research Institutes of Sweden.
    Fall, Andreas
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Wijeratne, Kosala
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Sandberg, Mats
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Laser-induced graphitization of a forest-based ink for use in flexible and printed electronics2020In: npj Flexible Electron., ISSN 2397-4621, Vol. 4, article id 17Article in journal (Refereed)
    Abstract [en]

    Laser-induced graphitization (LIG) is a method of converting a carbon-rich precursor into a highly conductive graphite-like carbon by laser scribing. This method has shown great promise as a versatile and low-cost patterning technique. Here we show for the first time how an ink based on cellulose and lignin can be patterned using screen printing followed by laser graphitization. Screen printing is one of the most commonly used manufacturing techniques of printed electronics, making this approach compatible with existing processing of various devices. The use of forest-based materials opens the possibility of producing green and sustainable electronics. Pre-patterning of the ink enables carbon patterns without residual precursor between the patterns. We investigated the effect of the ink composition, laser parameters, and additives on the conductivity and structure of the resulting carbon and could achieve low sheet resistance of 3.8 Ω sq-1 and a high degree of graphitization. We demonstrated that the process is compatible with printed electronics and finally manufactured a humidity sensor which uses lignin as the sensing layer and graphitized lignin as the electrodes.

  • 49.
    Edberg, Jesper
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware. Digital Cellulose Center, Sweden.
    Mulla, Yusuf
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware. Digital Cellulose Center, Sweden.
    Hosseinaei, Omid
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design. Digital Cellulose Center, Sweden.
    Ul Hassan Alvi, Naveed
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware. Digital Cellulose Center, Sweden.
    Beni, Valerio
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware. Digital Cellulose Center, Sweden.
    A Forest-Based Triboelectric Energy Harvester2022In: Global Challenges, E-ISSN 2056-6646, Vol. 6, no 10, article id 2200058Article in journal (Refereed)
    Abstract [en]

    Triboelectric nanogenerators (TENGs) are a new class of energy harvesting devices that have the potential to become a dominating technology for producing renewable energy. The versatility of their designs allows TENGs to harvest mechanical energy from sources like wind and water. Currently used renewable energy technologies have a restricted number of materials from which they can be constructed, such as metals, plastics, semiconductors, and rare-earth metals. These materials are all non-renewable in themselves as they require mining/drilling and are difficult to recycle at end of life. TENGs on the other hand can be built from a large repertoire of materials, including materials from bio-based sources. Here, a TENG constructed fully from wood-derived materials like lignin, cellulose, paper, and cardboard, thus making it 100% green, recyclable, and even biodegradable, is demonstrated. The device can produce a maximum voltage, current, and power of 232 V, 17 mA m–2, and 1.6 W m–2, respectively, which is enough to power electronic systems and charge 6.5 µF capacitors. Finally, the device is used in a smart package application as a self-powered impact sensor. The work shows the feasibility of producing renewable energy technologies that are sustainable both with respect to their energy sources and their material composition. © 2022 The Authors. 

  • 50.
    Eng, Mattias P.
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Lövberg, Andreas
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Misiorny, Maciej
    QRTECH AB, Sweden.
    Söderkvist Vermelin, Wilhelm
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Brinkfeldt, Klas
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Mishra, Madhav
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Simple Hybrid Model for Estimating Remaining Useful Life of SiC MOSFETs in Power Cycling Experiments2023Conference paper (Refereed)
    Abstract [en]

    Recording and prediction of the accumulated damage, which will eventually lead to the failure of power electronic modules, is an aspect of high importance for power electronic systems design and, in particular, for development of Prognostic and Health Management (PHM) schemes for in-field applications. To this end, this paper presents a simple and cost-effective prognostic method for predicting the remaining useful life (RUL) of TO-247 packaged silicon carbide (SiC) metal-oxide semiconductor field-effect transistors (MOSFETs) subjected to power cycling experiments. The model assumes that the major failure mode is bond-wire lift-off and uses a damage accumulation scheme based on Paris’ crack law. The only inputs to the model are historical data on the average junction temperature swing and the temperaturecompensated drain-source ON-state resistance at the peak temperature of the current cycle. Using only these two input values, the model is shown to predict RUL with surprising accuracy for the range of constant current loads determining cycling conditions under which the test data series have been acquired. This work is a first step in an ongoing project towards building more elaborate prognostic schemes for RUL-determination of SiC power MOSFETs in actual working conditions, using physics-informed neural networks (PINNs).

1234 1 - 50 of 173
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