| 1. |
- Belaineh Yilma, Dagmawi, et al.
(författare)
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Printable carbon-based supercapacitors reinforced with cellulose and conductive polymers
- 2022
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Ingår i: Journal of Energy Storage. - : Elsevier Ltd. - 2352-152X .- 2352-1538. ; 50
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 2. |
- Brill, J. W., et al.
(författare)
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Frequency-dependent photothermal measurement of transverse thermal diffusivity of organic semiconductors
- 2015
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Ingår i: Journal of Applied Physics. - : AMER INST PHYSICS. - 0021-8979 .- 1089-7550. ; 118:23, s. 235501-
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Tidskriftsartikel (refereegranskat)abstract
- We have used a photothermal technique, in which chopped light heats the front surface of a small (similar to 1 mm(2)) sample and the chopping frequency dependence of thermal radiation from the back surface is measured with a liquid-nitrogen-cooled infrared detector. In our system, the sample is placed directly in front of the detector within its dewar. Because the detector is also sensitive to some of the incident light, which leaks around or through the sample, measurements are made for the detector signal that is in quadrature with the chopped light. Results are presented for layered crystals of semiconducting 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-pn) and for papers of cellulose nanofibrils coated with semiconducting poly(3,4-ethylene-dioxythiophene): poly (styrene-sulfonate) (NFC-PEDOT). For NFC-PEDOT, we have found that the transverse diffusivity, smaller than the in-plane value, varies inversely with thickness, suggesting that texturing of the papers varies with thickness. For TIPS-pn, we have found that the interlayer diffusivity is an order of magnitude larger than the in-plane value, consistent with previous estimates, suggesting that low-frequency optical phonons, presumably associated with librations in the TIPS side groups, carry most of the heat. (C) 2015 AIP Publishing LLC.
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| 3. |
- Brooke, Robert, et al.
(författare)
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Controlling the electrochromic properties of conductive polymers using UV-light
- 2018
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Ingår i: Journal of Materials Chemistry C. - : ROYAL SOC CHEMISTRY. - 2050-7526 .- 2050-7534. ; 6:17, s. 4663-4670
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Tidskriftsartikel (refereegranskat)abstract
- The phenomenon of electrochromism in conductive polymers is well known and has been exploited in many scientific reports. Using a newly developed patterning technique for conductive polymers, we manufactured high-resolution electrochromic devices from the complementary polymers PEDOT and polypyrrole. The technique, which combines UV-light exposure with vapor phase polymerization, has previously only been demonstrated with the conductive polymer PEDOT. We further demonstrated how the same technique can be used to control the optical properties and the electrochromic contrast in these polymers. Oxidant exposure to UV-light prior to vapor phase polymerization showed a reduction in polymer electrochromic contrast allowing high-resolution (100 mu m) patterns to completely disappear while applying a voltage bias due to their optical similarity in one redox state and dissimilarity in the other. This unique electrochromic property enabled us to construct devices displaying images that appear and disappear with the change in applied voltage. Finally, a modification of the electrochromic device architecture permitted a dual image electrochromic device incorporating patterned PEDOT and patterned polypyrrole on the same electrode, allowing the switching between two different images.
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| 4. |
- Brooke, Robert, 1989-, et al.
(författare)
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Greyscale and paper electrochromic polymer displays by UV patterning
- 2019
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Ingår i: Polymers. - : MDPI AG. - 2073-4360. ; 11:2
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Tidskriftsartikel (refereegranskat)abstract
- Electrochromic devices have important implications as smart windows for energy efficient buildings, internet of things devices, and in low-cost advertising applications. While inorganics have so far dominated the market, organic conductive polymers possess certain advantages such as high throughput and low temperature processing, faster switching, and superior optical memory. Here, we present organic electrochromic devices that can switch between two high-resolution images, based on UV-patterning and vapor phase polymerization of poly(3,4- ethylenedioxythiophene) films. We demonstrate that this technique can provide switchable greyscale images through the spatial control of a UV-light dose. The color space was able to be further altered via optimization of the oxidant concentration. Finally, we utilized a UV-patterning technique to produce functional paper with electrochromic patterns deposited on porous paper, allowing for environmentally friendly electrochromic displays.
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| 5. |
- Brooke, Robert, 1989-, et al.
(författare)
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Large-scale paper supercapacitors on demand
- 2022
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Ingår i: Journal of Energy Storage. - : Elsevier Ltd. - 2352-152X .- 2352-1538. ; 50
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Tidskriftsartikel (refereegranskat)abstract
- 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
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| 6. |
- 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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| 7. |
- Brooke, Robert, 1989-, et al.
(författare)
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Nanocellulose based carbon ink and its application in electrochromic displays and supercapacitors
- 2021
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Ingår i: Flexible and Printed Electronics. - : IOP Publishing Ltd. - 2058-8585. ; 6:4
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Tidskriftsartikel (refereegranskat)abstract
- 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).
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| 8. |
- Brooke, Robert, 1989-, et al.
(författare)
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Paper Electronics Utilizing Screen Printing and Vapor Phase Polymerization
- 2023
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Ingår i: Advanced Sustainable Systems. - : John Wiley and Sons Inc. - 2366-7486. ; 7:7
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 9. |
- Brooke, Robert, 1989-, et al.
(författare)
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Supercapacitors on demand : All-printed energy storage devices with adaptable design
- 2019
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Ingår i: Flexible and Printed Electronics. - : Institute of Physics Publishing. - 2058-8585. ; 4:1
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Tidskriftsartikel (refereegranskat)abstract
- Demands on the storage of energy have increased for many reasons, in part driven by household photovoltaics, electric grid balancing, along with portable and wearable electronics. These are fast-growing and differentiated applications that need large volume and/or highly distributed electrical energy storage, which then requires environmentally friendly, scalable and flexible materials and manufacturing techniques. However, the limitations on current inorganic technologies have driven research efforts to explore organic and carbon-based alternatives. Here, we report a conducting polymer:cellulose composite that serves as the active material in supercapacitors which has been incorporated into all-printed energy storage devices. These devices exhibit a specific capacitance of ≈90 F g -1 and an excellent cyclability (>10 000 cycles). Further, a design concept coined 'supercapacitors on demand' is presented, which is based on a printing-cutting-folding procedure, that provides us with a flexible production protocol to manufacture supercapacitors with adaptable configuration and electrical characteristics.
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| 10. |
- Chen, Shangzhi, et al.
(författare)
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Redox-tunable structural colour images by UV-patterned conducting polymer nanofilms on metal surfaces
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Precise manipulation of light-matter interaction has enabled a wide variety of approaches to create bright and vivid structural colours. 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 significantly impede their further development towards flexible, large-scale, and switchable devices compatible with facile and cost-effective production. Herein, we present a simple and efficient method to generate structural colours based on nanoscale conducting polymer films prepared on metallic surfaces via vapour 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 colours from violet to red. Together with greyscale photomasks this enables fabrication of high-resolution colour images using single exposure steps. We further demonstrate spatiotemporal tuning of the structurally coloured surfaces and images via electrochemical modulation of the polymer redox state. The simple structure, facile fabrication, wide colour gamut, and dynamic colour tuning make this concept competitive for future multi-functional and smart displays.
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