| 1. |
- Delekta, Szymon Sollami, et al.
(författare)
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Drying-Mediated Self-Assembly of Graphene for Inkjet Printing of High-Rate Micro-supercapacitors
- 2020
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Ingår i: Nano-Micro Letters. - : Springer. - 2311-6706 .- 2150-5551. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Scalable fabrication of high-rate micro-supercapacitors (MSCs) is highly desired for on-chip integration of energy storage components. By virtue of the special self-assembly behavior of 2D materials during drying thin films of their liquid dispersion, a new inkjet printing technique of passivated graphene micro-flakes is developed to directly print MSCs with 3D networked porous microstructure. The presence of macroscale through-thickness pores provides fast ion transport pathways and improves the rate capability of the devices even with solid-state electrolytes. During multiple-pass printing, the porous microstructure effectively absorbs the successively printed inks, allowing full printing of 3D structured MSCs comprising multiple vertically stacked cycles of current collectors, electrodes, and sold-state electrolytes. The all-solid-state heterogeneous 3D MSCs exhibit excellent vertical scalability and high areal energy density and power density, evidently outperforming the MSCs fabricated through general printing techniques.[Figure not available: see fulltext.].
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| 2. |
- Delekta, Szymon Sollami, et al.
(författare)
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Fully inkjet printed ultrathin microsupercapacitors based on graphene electrodes and a nano-graphene oxide electrolyte
- 2019
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Ingår i: Nanoscale. - : Royal Society of Chemistry. - 2040-3364 .- 2040-3372. ; 11:21, s. 10172-10177
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Tidskriftsartikel (refereegranskat)abstract
- The advance of miniaturized and low-power electronics has a striking impact on the development of energy storage devices with constantly tougher constraints in terms of form factor and performance. Microsupercapacitors (MSCs) are considered a potential solution to this problem, thanks to their compact device structure. Great efforts have been made to maximize their performance with new materials like graphene and to minimize their production cost with scalable fabrication processes. In this regard, we developed a full inkjet printing process for the production of all-graphene microsupercapacitors with electrodes based on electrochemically exfoliated graphene and an ultrathin solid-state electrolyte based on nano-graphene oxide. The devices exploit the high ionic conductivity of nano-graphene oxide coupled with the high electrical conductivity of graphene films, yielding areal capacitances of up to 313 mu F cm-2 at 5 mV s-1 and high power densities of up to 4 mW cm-3 with an overall device thickness of only 1 mu m.
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| 3. |
- Delekta, Szymon Sollami, et al.
(författare)
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Inkjet printed highly transparent and flexible graphene micro-supercapacitors
- 2017
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Ingår i: Nanoscale. - : Royal Society of Chemistry. - 2040-3364 .- 2040-3372. ; 9:21, s. 6998-7005
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Tidskriftsartikel (refereegranskat)abstract
- Modern energy storage devices for portable and wearable technologies must fulfill a number of requirements, such as small size, flexibility, thinness, reliability, transparency, manufacturing simplicity and performance, in order to be competitive in an ever expanding market. To this end, a comprehensive inkjet printing process is developed for the scalable and low-cost fabrication of transparent and flexible micro-supercapacitors. These solid-state devices, with printed thin films of graphene flakes as interdigitated electrodes, exhibit excellent performance versus transparency (ranging from a single-electrode areal capacitance of 16 mu F cm(-2) at transmittance of 90% to a capacitance of 99 mu F cm(-2) at transmittance of 71%). Also, transparent and flexible devices are fabricated, showing negligible capacitance degradation during bending. The ease of manufacturing coupled with their great capacitive properties opens up new potential applications for energy storage devices ranging from portable solar cells to wearable sensors.
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| 4. |
- Delekta, Szymon Sollami, et al.
(författare)
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Wet Transfer of Inkjet Printed Graphene for Microsupercapacitors on Arbitrary Substrates
- 2019
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Ingår i: ACS Applied Energy Materials. - : American Chemical Society (ACS). - 2574-0962. ; 2:1, s. 158-163
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Tidskriftsartikel (refereegranskat)abstract
- Significant research interest is being devoted to exploiting the properties of graphene but the difficult integration on various substrates limits its use. In this regard, we developed a transfer technique that allows the direct deposition of inkjet printed graphene devices on arbitrary substrates, even 3D objects and living plants. With this technique, we fabricated micro-supercapacitors, which exhibited good adhesion on almost all substrates and no performance degradation induced by the process. Specifically, the microsupercapacitor on an orchid leaf showed an areal capacitance as high as 441 mu F cm(-2) and a volumetric capacitance of 1.16 F cm(-3). This technique can boost the use of graphene in key technological applications, such as self powered epidermal electronics and environmental monitoring systems.
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| 5. |
- Li, Jiantong, 1980-, et al.
(författare)
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Scalable Fabrication and Integration of Graphene Microsupercapacitors through Full Inkjet Printing
- 2017
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 11:8, s. 8249-8256
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Tidskriftsartikel (refereegranskat)abstract
- A simple full-inkjet-printing technique is developed for the scalable fabrication of graphene-based microsupercapacitors (MSCs) on various substrates. High-performance graphene inks are formulated by integrating the electrochemically exfoliated graphene with a solvent exchange technique to reliably print graphene interdigitated electrodes with tunable geometry and "thickness. Along with the printed polyelectrolyte, poly(4-styrenesulfonic acid), the fully printed graphene-based MSCs attain the highest areal capacitance of similar to 0.7 mF/cm(2), substantially advancing the state-of-art of all-solid-state MSCs with printed graphene electrodes. The full printing solution enables scalable fabrication of MSCs and effective connection of them in parallel and/or in series at various scales. Remarkably, more than 100 devices have been connected to form large-scale MSC arrays as power banks on both silicon wafers and Kapton. Without any extra protection or encapsulation, the MSC arrays can be reliably charged up to 12 V and retain the performance even 8 months after fabrication.
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| 6. |
- Loiko, Pavel, et al.
(författare)
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Inkjet-Printing of Graphene Saturable Absorbers for similar to 2 mu m Bulk and Waveguide Lasers
- 2017
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Ingår i: 2017 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO). - : IEEE. - 9781943580279
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Konferensbidrag (refereegranskat)abstract
- We report on inkjet-printing of graphene saturable absorbers (SAs) suitable for passive Q-switching of similar to 2-mu m bulk and waveguide lasers. Using graphene-SA in a microchip Tm:KLu(WO4)(2) laser, 1.2 mu J/136 ns pulses are generated at 1917 nm.
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| 7. |
- Loiko, Pavel, et al.
(författare)
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Inkjet-printing of graphene saturable absorbers for similar to 2 mu m bulk and waveguide lasers
- 2018
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Ingår i: Optical Materials Express. - : Optical Society of America. - 2159-3930 .- 2159-3930. ; 8:9, s. 2803-2814
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Tidskriftsartikel (refereegranskat)abstract
- A technique for inkjet-printing of graphene saturable absorbers (SAs) for similar to 2-mu m bulk and waveguide lasers is presented. Based on distillation-assisted solvent exchange to fabricate high-concentration graphene inks, this technique is capable of producing few-layer graphene films of arbitrary shape. Absorption saturation of graphene printed on glass is demonstrated at similar to 1.56 mu m for picosecond and femtosecond pulses indicating a large fraction of the saturable losses. Inkjet-printed transmission-type graphene SAs are applied in passively Q-switched nanosecond thulium (Tm) microchip and planar waveguide lasers. The Tm microchip laser generates 136 ns / 1.2 mu J pulses at 1917 nm with a repetition rate of 0.37 MHz with a Q-switching conversion efficiency reaching 65%. The planar waveguide laser generates 98 ns / 21 nJ pulses at 1834 nm at a repetition rate in the MHz-range. The inkjet-printing technique is promising for production of patterned SAs for waveguide lasers.
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| 8. |
- Mishukova, Viktoriia, et al.
(författare)
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Facile fabrication of graphene-based high-performance microsupercapacitors operating at a high temperature of 150 °C
- 2021
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Ingår i: Nanoscale Advances. - : Royal Society of Chemistry (RSC). - 2516-0230. ; 3:16, s. 4674-4679
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Tidskriftsartikel (refereegranskat)abstract
- Many industry applications require electronic circuits and systems to operate at high temperatures over 150 °C. Although planar microsupercapacitors (MSCs) have great potential for miniaturized on-chip integrated energy storage components, most of the present devices can only operate at low temperatures (<100 °C). In this work, we have demonstrated a facile process to fabricate activated graphene-based MSCs that can work at temperatures as high as 150 °C with high areal capacitance over 10 mF cm−2and good cycling performance. Remarkably, the devices exhibit no capacitance degradation during temperature cycling between 25 °C and 150 °C, thanks to the thermal stability of the active components.
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| 9. |
- Sollami Delekta, Szymon, 1990-
(författare)
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Inkjet Printing of Graphene-based Microsupercapacitors for Miniaturized Energy Storage Applications
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Printing technologies are becoming increasingly popular because they enable the large-scale and low-cost production of functional devices with various designs, functions, mechanical properties and materials. Among these technologies, inkjet printing is promising thanks to its direct (mask-free) patterning, non-contact nature, low material waste, resolution down to 10 µm, and compatibility with a broad range of materials and substrates. As a result, inkjet printing has applications in several fields like wearables, opto-electronics, thin-film transistors, displays, photovoltaic devices, and in energy storage. It's in energy storage that the technique shows its full potential by allowing the production of miniaturized devices with a compact form factor, high power density and long cycle life, called microsupercapacitors (MSCs). To this end, graphene has a number of remarkable properties like high electrical conductivity, large surface area, elasticity and transparency, making it a top candidate as an electrode material for MSCs.Some key drawbacks limit the use of inkjet printing for the production of graphene-based MSCs. This thesis aims at improving its scalability by producing fully inkjet printed devices, and extending its applications through the integration of inkjet printing with other fabrication techniques.MSCs typically rely on the deposition by hand of gel electrolyte that is not printable or by submerging the whole structure into liquid electrolyte. Because of this, so far large-scale production of more than 10 interconnected devices has not been attempted. In this thesis, a printable gel electrolyte ink based on poly(4-styrene sulfonic acid) was developed, allowing the production of large arrays of more than 100 fully inkjet printed devices connected in series and parallel that can be reliably charged up to 12 V. Also, a second electrolyte ink based on nano-graphene oxide, a solid-state material with high ionic conductivity, was formulated to optimize the volumetric performance of these devices. The resulting MSCs were also fully inkjet printed and exhibited an overall device thickness of around 1 µm, yielding a power density of 80 mW cm-3.Next, the use of inkjet printing of graphene was explored for the fabrication of transparent MSCs. This application is typically hindered by the so-called coffee-ring effect, which creates dark deposits on the edges of the drying patterns and depletes material from the inside area. In light of this issue, inkjet printing was combined with etching to remove the dark deposits thus leaving uniform and thin films of graphene with vertical sidewalls. The resulting devices showed a transmittance of up to 90%.Finally, the issue of the substrate compatibility of inkjet printed graphene was addressed. Although inkjet printing is considered to have broad substrate versatility, it is unreliable on hydrophilic or porous substrates and most inks (including graphene inks) require thermal annealing that damages substrates that are not resistant to heat. Accordingly, a technique based on inkjet printing and wet transfer was developed to reliably deposit graphene-based MSCs on a number of substrates, including flat, 3D, porous, plastics and biological (plants and fruits) with adverse surfaces.The contributions of this thesis have the potential to boost the use of inkjet printed MSCs in applications requiring scalability and resolution (e.g. on-chip integration) as well as applications requiring conformability and versatility (e.g. wearable electronics).
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| 10. |
- Xia, Zhenyuan, 1983, et al.
(författare)
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Selective deposition of metal oxide nanoflakes on graphene electrodes to obtain high-performance asymmetric micro-supercapacitors
- 2021
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Ingår i: Nanoscale. - 2040-3372 .- 2040-3364. ; 13:5, s. 3285-3294
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Tidskriftsartikel (refereegranskat)abstract
- To meet the charging market demands of portable microelectronics, there has been a growing interest in high performance and low-cost microscale energy storage devices with excellent flexibility and cycling durability. Herein, interdigitated all-solid-state flexible asymmetric micro-supercapacitors (A-MSCs) were fabricated by a facile pulse current deposition (PCD) approach. Mesoporous Fe2O3 and MnO2 nanoflakes were functionally coated by electrodeposition on inkjet-printed graphene patterns as negative and positive electrodes, respectively. Our PCD approach shows significantly improved adhesion of nanostructured metal oxide with crack-free and homogeneous features, as compared with other reported electrodeposition approaches. The as-fabricated Fe2O3/MnO2 A-MSCs deliver a high volumetric capacitance of 110.6 F cm(-3) at 5 mu A cm(-2) with a broad operation potential range of 1.6 V in neutral LiCl/PVA solid electrolyte. Furthermore, our A-MSC devices show a long cycle life with a high capacitance retention of 95.7% after 10 000 cycles at 100 mu A cm(-2). Considering its low cost and potential scalability to industrial levels, our PCD technique could be an efficient approach for the fabrication of high-performance MSC devices in the future.
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