| 1. |
- Tran, Van Chinh, 1990-
(författare)
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Wood Templated Organic Electronics
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In today’s digital era, electronics are integral to most activities in our daily lives, offering swift and global communication, powerful data processing tools, and advanced sensor devices. However, there are drawbacks to the exponentially growing demand for electronics, such as the depletion of fossil resources, and the complexities surrounding recycling electronic waste (E-waste). As we gradually step into the era of sustainability, it is necessary to explore alternative resources and develop greener electronic technologies. For this purpose, organic electronics (OE) has emerged as an interesting alternative, owning to its potential for low-energy fabrication and use of organic materials composed of Earth-abundant elements.The term "organic electronics" has been used widely to refer to electrical devices crafted from organic materials, typically semiconducting polymers (sCPs). This arises from the fact that most developed OE devices such as solar cells, transistors, supercapacitors, and batteries are centered around such materials. Along with the development of different semiconducting polymer varieties, materials from various natural resources have also been explored for devices’ electrodes, binders, and electrolytes. Among them, materials from the forest have emerged as abundant, renewable, and valuable options. For many years, wood has been tailored and utilized as a device template, while its components including cellulose fibrils and lignin have been widely used as structural or active components in OE. Lignin has now become an important electrode and electrolyte active material in energy storage devices.This thesis presents new approaches and findings in the utilization of wood and lignin as active components in different OE applications. The thesis centers around two primary themes, in which the first involves the development and utilization of conductive wood (CW), containing lignin, and lignin nanoparticles (LNPs) for supercapacitors and battery applications. The second theme focuses on developing and employing conductive wood as an active electrode in the creation of a wood electrochemical transistor. Within the first theme, I have uncovered the potential of storing electricity in wood utilizing its redox-active component, native lignin. The discovery is reinforced by the successful employment of LNPs as active materials in an organic battery. Within the second theme, I have demonstrated the world's first wooden transistor, characterized its electronic performance, and discussed the pretreatment procedure of the wood substrate that is necessary for achieving a working device. This thesis is anticipated to contribute to new and valuable knowledge for encouraging the development of low-cost and sustainable OE in the future.
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| 2. |
- Wu, Zhixing, 1990-, et al.
(författare)
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Conducting Polymer‐Based e‐Refinery for Sustainable Hydrogen Peroxide Production
- 2023
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Ingår i: Energy & Environmental Materials. - : Wiley-Blackwell. - 2575-0356.
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Tidskriftsartikel (refereegranskat)abstract
- Electrocatalysis enables the industrial transition to sustainable production of chemicals using abundant precursors and electricity from renewable sources. De-centralized production of hydrogen peroxide (H2O2) from water and oxygen of air is highly desirable for daily life and industry. We report an effective electrochemical refinery (e-refinery) for H2O2 by means of electrocatalysis-controlled comproportionation reaction (2(H)O + O -> 2(HO)), feeding pure water and oxygen only. Mesoporous nickel (II) oxide (NiO) was used as electrocatalyst for oxygen evolution reaction (OER), producing oxygen at the anode. Conducting polymer poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) drove the oxygen reduction reaction (ORR), forming H2O2 on the cathode. The reactions were evaluated in both half-cell and device configurations. The performance of the H2O2 e-refinery, assembled on anion-exchange solid electrolyte and fed with pure water, was limited by the unbalanced ionic transport. Optimization of the operation conditions allowed a conversion efficiency of 80%.
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| 3. |
- Yang, Hongli, 1992-
(författare)
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Ion Transport in Cross-linked Nanocellulose Membranes
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Ion-selective membranes, which allow ions with a certain charge and/or size to pass through while blocking other ions, have attracted much attention due to their diverse applications and outstanding roles in overcoming problems related to energy. In addition to the performance, the financial cost and renewability of materials are equally significant in the development of these membranes. Commonly, ion-selective membranes are prepared from traditional synthetic polymers that have put a heavy burden on the environment. Therefore, exploring low-cost, environment-friendly materials as the substitution of traditional polymers for ion-selective membranes will be beneficial from a sustainable perspective.Nanocellulose is a promising candidate for the next generation of ionic membranes due to its unique chemical structure and suitable physical dimensions. Furthermore, it can be produced from cellulose, which is the most abundant biopolymer on earth. Nanocellulose has many hydroxyl groups that provide many possibilities to introduce ion-functionalized groups on the cellulose chain through chemical treatment and modification. In addition, the physical entanglement of cellulose nanofibrils can generate a nanoscale porous structure that improves the ion permselectivity of membranes and provides a strong network that enhances the toughness of membranes. Among the disadvantages of nanocellulose-based products is poor wet stability due to the swelling induced by their hydrophilicity. This problem can be effectively solved using covalent cross-linking.This thesis aims to develop nanocellulose-based ionic membranes with excellent ionic transport properties as well as good wet stability and to explore their potential applications. First, the nanocellulose membranes cross-linked by 1,2,3,4-butanetetracarboxylic acid (BTCA) were developed. The relationship between the amount of cross-linker and the membranes’ pore size, charge density, and ionic transport properties was demonstrated. Based on the above fundamental understanding of the membranes’ performance, especially ion conductivity, and selectivity, their performance was then investigated in two potential applications, including osmotic power generators and redox flow batteries. Finally, the original cross-linked membrane, which is negatively charged, was combined with a corresponding membrane with positive surface charges to obtain bipolar membranes, which can be used for rectification. The properties of these bipolar membranes were investigated, with the conclusion that they can be used as an ionic diode under certain conditions.
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| 4. |
- Zhang, Silan, 1992-
(författare)
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Organic Electrochemical Transistors : Materials and Challenges
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The use of organic mixed ionic-electronic conductors (OMIECs) has demonstrated the potential to transform the field of bioelectronics, spanning from medical diagnostics to neuromorphic computing hardware. To keep up with the fast-paced demands, it is crucial to develop customizable device fabrication, design new materials, improve operation stability, and explore the ion-electron interactions within OMIECs. This thesis explores the application of OMIECs in organic electrochemical transistors (OECTs), a crucial component of a range of organic bioelectronic devices. To meet applications requiring rapid design iterations and leveraging digitally enabled direct-write techniques, we developed a novel approach for fabricating fully 3D-printed OECTs using a direct-write additive process. This method involves utilizing 3D printable inks with conductive, semiconductive, insulating, and electrolyte properties. The resulting fully 3D-printed OECTs operate in the depletion mode and can be produced on flexible substrates, ensuring excellent mechanical durability and resilience in various environmental conditions. These 3D-printed OECTs exhibit impressive dopamine biosensing capabilities, detecting concentrations as low as 6 µM without the need for metal gate electrodes. Furthermore, they demonstrate long-term memory response lasting up to approximately 1 hour, highlighting their potential for diverse applications such as sensors and neuromorphic hardware. We have addressed the issue of sluggish response times in printed OECTs by utilizing multi-walled carbon nanotubes (MWCNTs) and the π-conjugated redox polymer called poly(benzimidazobenzo-phenanthroline) (BBL) to create high-performing n-type OECTs. By incorporating MWCNTs, we were able to improve the electron mobility of the transistors by more than 10 times, resulting in a rapid response time of just 15 ms and a high μC* value (which is the product of electron mobility and volumetric capacitance) of approximately 1 F cm–1 V−1 s−1. These breakthroughs have allowed us to develop complementary inverters that have a voltage gain of over 16, a significant worst-case noise margin at a supply voltage lower than 0.6 V and consume less than 1 µW of power. However, the operational stability of complementary inverters is hindered by the degradation of p-type OMIECs. The oxygen reduction reaction (ORR) is a common electrochemical side reaction that poses challenges to the stability of OECTs, but the underlying connection between ORR and material degradation remains poorly understood. In our investigation, we examined the influence of ORR on the stability and degradation mechanisms of thiophene-based OECTs. Our findings reveal that the polymer backbone experiences degradation as a result of the pH increase during ORR. To address this issue, we introduced a protective polymer glue layer between the semiconductor channel and the aqueous electrolyte, effectively suppressing the occurrence of ORR and significantly enhancing the stability of the OECTs. This improvement is evident in the nearly 90% retention of current during ≈2 hours of cycling in the saturation regime. Finally, we investigated the ionic-electronic transport properties in BBL-based OECTs using various electrolytes. We found that the peak drain current is achieved at a doping level of 1 electron per repeating unit, decreasing thereafter. The interaction between ions and the polymer reduces the voltage needed for this level of doping but also lowers the peak drain current. Unlike thiophene-based OECTs, larger cation sizes don't improve BBL-based OECT performance. Additionally, Lewis acids adversely affect BBL's electrical properties due to their impact on the polymer microstructure. We hope these studies will inspire our peers in the field of materials synthesis, device processing, and scalable digital techniques, paving the way for next-generation, reliable, and safe bioelectronics.
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| 5. |
- Oikonomou, Vasileios, 1992-
(författare)
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Cellulose-based Conducting 3D and 2D Composites for Applications in Plant Science and Responsive Systems
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Polymers (Greek: poly=many, meros=part) are large molecules made up of many small parts (monomers) in a repetitive way, as a term was introduced for the first time (1833) by the Swedish chemist, Jöns Jakob Berzelius. By the combination of different monomers, the resulting polymer can exhibit various properties, such as biodegradability, photosensitivity and electrical conductivity. The latter is the main characteristic of the polymers included in this thesis. Since their commercialization, in the late 20th century soft and biocompatible conductive polymers have been substituting stiff and bio-tolerable metals in numerous cases, especially in the medical field for in vivo applications. Polymers can also be found in nature, as a product of the life cycles of animals, plants and microorganisms. The variety of natural polymers is vast, and they are categorized mainly into the groups of polysaccharides, polypeptides and polynucleotides. In these categories belong some of the most well known and investigated materials, for instance, DNA, proteins, silk and cellulose. The combination of synthetic materials with natural materials has intrigued the scientific community for many decades, as a way to form functional materials with hybrid properties. In this thesis, synthetic polymers, particularly conjugated polymers were combined with cellulose, the most abundant biopolymer on earth to form 2D and 3D conducting composites that can find application in plant science and stimuli-responsive systems. In the first part of this thesis, the widely used conjugated polymer PEDOT:PSS was combined with cellulose nanofibers to form 3D porous conducting scaffolds. The scaffolds were developed by freeze-drying method and their electrochemical, mechanical and structural properties were characterized. We investigated the effect of the freezing method on the scaffold properties and found a correlation between the mechanical properties and the pore wall thickness. Furthermore, with micro-CT, we could characterize in detail the bulk structure of the scaffolds and investigate how the incorporation of carbon fibers as addressing electrodes influences the porosity (paper 1). Next, we applied the conducting scaffolds for stimulating plant growth. The plant of our choice was barley, a very important crop, which was grown within the scaffold and the roots were integrated within the scaffold’s pores. We demonstrated that plants grow in the scaffolds under sterile conditions, as well as in agar which is the standard medium used in plant sterile culture. Taking a step ahead, we developed a non-sterile hydroponics setup, where the plants could grow without any contamination. Furthermore, we applied different protocols of electric stimulation to the scaffolds for various time periods and polarizations, achieving at the end a 40% increase in the plant biomass for the stimulated plants. We investigated the growth of the plants and concluded that the enhancement of growth was taking place after the stimulation period with growth enhancement both to roots and shoots (paper 2). In the second part of the thesis, we harnessed the unique electroswelling capabilities of the polythiophene-based polymer p(g3T2), with two different approaches. Initially, we demonstrated the ability of the p(g3T2) material to expand reversibly on a 2D mesh when electrochemically addressed. We optimized the coating on the metallic mesh with fixed pore size and developed an electroactive filter with tunable porosity that could modulate the flow of a system on demand (paper 3). Although p(g3T2) has great potential for various applications, it is processed from hazardous organic solvents, such as chloroform. Therefore, we addressed this issue and developed a protocol where p(g3T2) is solubilized in ethanol, which enables the coating of a plethora of substrates that chloroform would dissolve. From a biodegradable 3D printed mesh of cellulose and polylactide to everyday labware we demonstrated that p(g3T2) can change the substrate properties when electrochemically addressed directly on the non-conducting substrate without the need for an underlying supporting electrode. Forming a biocompatible substrate able to facilitate tissue engineering studies(paper 4). Overall, in this thesis, we demonstrated how synthetic materials can be combined with natural materials to form functional composites with hybrid properties. Firstly, by combining the mechanical characteristics of cellulose and the mixed ionic electronic conductivity of PEDOT:PSS we can obtain a 3D phytocompatible aerogel that can have desired pore size, undergo mechanical compression and act as an active hydroponic substrate for stimulating plant growth. Then we demonstrated how polymers with controllable volume change, such as the polythiophene-based conjugated polymer p(g3T2), can be combined with everyday materials paving the way for stimuli responsive systems such as electroactive filters, and when used with a green solvent can modify everyday labware used for in vitro experiments.
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| 6. |
- Ail, Ujwala, 1980-, et al.
(författare)
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Optimization of Non-Pyrolyzed Lignin Electrodes for Sustainable Batteries
- 2023
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Ingår i: ADVANCED SUSTAINABLE SYSTEMS. - : WILEY-V C H VERLAG GMBH. - 2366-7486. ; 7:2
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Tidskriftsartikel (refereegranskat)abstract
- Lignin, a byproduct from the pulp industry, is one of the redox active biopolymers being investigated as a component in the electrodes for sustainable energy storage applications. Due to its insulating nature, it needs to be combined with a conductor such as carbon or conducting polymer for efficient charge storage. Here, the lignin/carbon composite electrodes manufactured via mechanical milling (ball milling) are reported. The composite formation, correlation between performance and morphology is studied by comparison with manual mixing and jet milling. Superior charge storage capacity with approximate to 70% of the total contribution from the Faradaic process involving the redox functionality of lignin is observed in a mechanically milled composite. In comparison, manual mix shows only approximate to 30% from the lignin storage participation while the rest is due to the electric double layer at the carbon-electrolyte interface. The significant participation of lignin in the ball milled composite is attributed to the homogeneous, intimate mixing of the carbon and the lignin leading the electronic carrier transported in the carbon phase to reach most of the redox group of lignin. A maximum capacity of 49 mAh g(-1) is obtained at charge/discharge rate of 0.25 A g(-1) for the sample milled for 60 min.
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| 7. |
- Brooke, Robert, 1989-, et al.
(författare)
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Nanocellulose and PEDOT:PSS composites and their applications
- 2023
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Ingår i: Polymer Reviews. - : Taylor and Francis Ltd.. - 1558-3724 .- 1558-3716. ; :2, s. 437-
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Tidskriftsartikel (refereegranskat)abstract
- 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).
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| 8. |
- Cherian, Dennis, 1989-, et al.
(författare)
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Flexible Organic Electronic Ion Pump Fabricated Using Inkjet Printing and Microfabrication for Precision In Vitro Delivery of Bupivacaine
- 2023
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Ingår i: Advanced Healthcare Materials. - : John Wiley and Sons Inc. - 2192-2640 .- 2192-2659. ; 12:24, s. 2300550-
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Tidskriftsartikel (refereegranskat)abstract
- The organic electronic ion pump (OEIP) is an on-demand electrophoretic drug delivery device, that via electronic to ionic signal conversion enables drug delivery without additional pressure or volume changes. The fundamental component of OEIPs is their polyelectrolyte membranes which are shaped into ionic channels that conduct and deliver ionic drugs, with high spatiotemporal resolution. The patterning of these membranes is essential in OEIP devices and is typically achieved using laborious microprocessing techniques. Here, the development of an inkjet printable formulation of polyelectrolyte is reported, based on a custom anionically functionalized hyperbranched polyglycerol (i-AHPG). This polyelectrolyte ink greatly simplifies the fabrication process and is used in the production of free-standing OEIPs on flexible polyimide (PI) substrates. Both i-AHPG and the OEIP devices are characterized, exhibiting favorable iontronic characteristics of charge selectivity and the ability to transport aromatic compounds. Further, the applicability of these technologies is demonstrated by the transport and delivery of the pharmaceutical compound bupivacaine to dorsal root ganglion cells with high spatial precision and effective nerve blocking, highlighting the applicability of these technologies for biomedical scenarios. © 2023 The Authors. Advanced Healthcare Materials published by Wiley-VCH GmbH.
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| 9. |
- Kumar, Divyaratan, 1995-, et al.
(författare)
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Zinc salt in "Water-in-Polymer Salt Electrolyte" for Zinc-Lignin Batteries: Electroactivity of the Lignin Cathode
- 2023
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Ingår i: ADVANCED SUSTAINABLE SYSTEMS. - : WILEY-V C H VERLAG GMBH. - 2366-7486. ; 7:4
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Tidskriftsartikel (refereegranskat)abstract
- Zn-ion batteries are one of the hot candidates for low-cost and sustainable secondary batteries. The hydrogen evolution and dendritic growth upon zinc deposition are todays challenges for that technology. One of the new strategies to cope with these issues is to use "water-in-salt" electrolyte (WISE), that is, super concentrated aqueous electrolytes, to broaden its electrochemical stability window (ESW), suppressing hydrogen evolution reaction (HER), and perturbing the dendritic growth. Herein, this work proposes to use "water-in-polymer salt" electrolyte (WIPSE) concept to mitigate the challenges with Zn ion batteries and bring this technology toward one of the cheapest, greenest, and most sustainable electrodes: Lignin-carbon (L-C) electrode. Potassium polyacrylate (PAAK) as WISE bears out as better electrolyte for L-C electrodes in terms of self-discharge, cyclic stability, and specific capacity compared to conventional electrolyte based on chemically cousin molecule potassium acetate. Zinc bis(trifluoromethanesulfonyl) imide (Zn(TFSI)(2)) added into WIPSE shows deposition and dissolution of Zn in Zn//Zn symmetric cell suggesting that Zn2+ are moving into the polyanionic network. Furthermore, the added bis (trifluor omethanesul fonyl) imide (TFSI-) metal salts trigger a approximate to 40% enhancement of the capacity of L-C electrode. These results show a new promising direction toward the development of cost-effective and sustainable Zn-lignin batteries.
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| 10. |
- Luo, Yifei, et al.
(författare)
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Technology Roadmap for Flexible Sensors
- 2023
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Ingår i: ACS Nano. - : American Chemical Society. - 1936-0851 .- 1936-086X. ; 17:6, s. 5211-5295
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Forskningsöversikt (refereegranskat)abstract
- Humans rely increasingly on sensors to address grand challenges and to improve quality of life in the era of digitalization and big data. For ubiquitous sensing, flexible sensors are developed to overcome the limitations of conventional rigid counterparts. Despite rapid advancement in bench-side research over the last decade, the market adoption of flexible sensors remains limited. To ease and to expedite their deployment, here, we identify bottlenecks hindering the maturation of flexible sensors and propose promising solutions. We first analyze challenges in achieving satisfactory sensing performance for real-world applications and then summarize issues in compatible sensor-biology interfaces, followed by brief discussions on powering and connecting sensor networks. Issues en route to commercialization and for sustainable growth of the sector are also analyzed, highlighting environmental concerns and emphasizing nontechnical issues such as business, regulatory, and ethical considerations. Additionally, we look at future intelligent flexible sensors. In proposing a comprehensive roadmap, we hope to steer research efforts towards common goals and to guide coordinated development strategies from disparate communities. Through such collaborative efforts, scientific breakthroughs can be made sooner and capitalized for the betterment of humanity.
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