| 1. |
- Del, Sepideh Khandan, et al.
(författare)
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Optimizing the optical and electrical properties of graphene ink thin films by laser-annealing
- 2015
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Ingår i: Current Opinion in Chemical Engineering. - : Institute of Physics (IOP). - 2211-3398. ; 2:1
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate a facile fabrication technique for graphene-based transparent conductive films. Highly flat and uniform graphene films are obtained through the incorporation of an efficient laser annealing technique with one-time drop casting of high-concentration graphene ink. The resulting thin films are uniform and exhibit a transparency of more than 85% at 550 nm and a sheet resistance of about 30 kΩ/sq. These values constitute an increase of 45% in transparency, a reduction of surface roughness by a factor of four and a decrease of 70% in sheet resistance compared to un-annealed films.
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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, et al.
(författare)
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All-solid-state micro-supercapacitors based on inkjet printed graphene electrodes
- 2016
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Ingår i: Applied Physics Letters. - : American Institute of Physics (AIP). - 0003-6951 .- 1077-3118. ; 109:12
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Tidskriftsartikel (refereegranskat)abstract
- The all-solid-state graphene-based in-plane micro-supercapacitors are fabricated simply through reliable inkjet printing of pristine graphene in interdigitated structure on silicon wafers to serve as both electrodes and current collectors, and a following drop casting of polymer electrolytes (polyvinyl alcohol/H3PO4). Benefiting from the printing processing, an attractive porous electrode microstructure with a large number of vertically orientated graphene flakes is observed. The devices exhibit commendable areal capacitance over 0.1 mF/cm(2) and a long cycle life of over 1000 times. The simple and scalable fabrication technique for efficient micro-supercapacitors is promising for on-chip energy storage applications in emerging electronics.
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| 6. |
- Li, Jiantong, et al.
(författare)
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Conductivity scaling in supercritical percolation of nanoparticles : not a power law
- 2015
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Ingår i: Nanoscale. - : Royal Society of Chemistry. - 2040-3364 .- 2040-3372. ; 7:8, s. 3424-3428
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Tidskriftsartikel (refereegranskat)abstract
- The power-law behavior widely observed in supercritical percolation systems of conductive nanoparticles may merely be a phenomenological approximation to the true scaling law not yet discovered. In this work, we derive a comprehensive yet simple scaling law and verify its extensive applicability to various experimental and numerical systems. In contrast to the power law which lacks theoretical backing, the new scaling law is explanatory and predictive, and thereby helpful to gain more new insights into percolation systems of conductive nanoparticles.
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| 7. |
- Li, Jiantong, et al.
(författare)
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Precise percolation thresholds of two-dimensional random systems comprising overlapping ellipses
- 2016
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Ingår i: Physica A. - : Elsevier. - 0378-4371 .- 1873-2119. ; 462, s. 940-950
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Tidskriftsartikel (refereegranskat)abstract
- This work explores the percolation thresholds of continuum systems consisting of randomly-oriented overlapping ellipses. High-precision percolation thresholds for various homogeneous ellipse systems with different aspect ratios are obtained from extensive Monte Carlo simulations based on the incorporation of Vieillard-Baron's contact function of two identical ellipses with our efficient algorithm for continuum percolation. In addition, we generalize Vieillard-Baron's contact function from identical ellipses to unequal ellipses, and extend the Monte Carlo algorithm to heterogeneous ellipse systems where the ellipses have different dimensions and/or aspect ratios. Based on the concept of modified excluded area, a general law is verified for precise prediction of percolation threshold for many heterogeneous ellipse systems. In particular, the study of heterogeneous ellipse systems gains insight into the apparent percolation threshold symmetry observed earlier in systems comprising unequal circles (Consiglio et al., 2004).
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| 8. |
- 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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| 9. |
- Li, Jiantong, et al.
(författare)
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Scalable Fabrication of 2D Semiconducting Crystals for Future Electronics
- 2015
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Ingår i: Electronics. - : MDPI. - 2079-9292. ; 4:4, s. 1033-1061
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Forskningsöversikt (refereegranskat)abstract
- Two-dimensional (2D) layered materials are anticipated to be promising for future electronics. However, their electronic applications are severely restricted by the availability of such materials with high quality and at a large scale. In this review, we introduce systematically versatile scalable synthesis techniques in the literature for high-crystallinity large-area 2D semiconducting materials, especially transition metal dichalcogenides, and 2D material-based advanced structures, such as 2D alloys, 2D heterostructures and 2D material devices engineered at the wafer scale. Systematic comparison among different techniques is conducted with respect to device performance. The present status and the perspective for future electronics are discussed.
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| 10. |
- Lobov, Gleb, et al.
(författare)
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Dynamic manipulation of optical anisotropy of suspended Poly-3-hexylthiophene nanofibers
- 2016
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Ingår i: Advanced Optical Materials. - : Wiley. - 2162-7568 .- 2195-1071. ; 4:10, s. 1651-1656
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Tidskriftsartikel (refereegranskat)abstract
- Poly-3-hexylthiophene (P3HT) nanofibers are 1D crystalline semiconducting nanostructures, which are known for their application in photovoltaics. Due to the internal arrangement, P3HT nanofibers possess optical anisotropy, which can be enhanced on a macroscale if nanofibers are aligned. Alternating electric field, applied to a solution with dispersed nanofibers, causes their alignment and serves as a method to produce solid layers with ordered nanofibers. The transmission ellipsometry measurements demonstrate the dichroic absorption and birefringence of ordered nanofibers in a wide spectral range of 400–1700 nm. Moreover, the length of nanofibers has a crucial impact on their degree of alignment. Using electric birefringence technique, it is shown that external electric field applied to the solution with P3HT nanofibers can cause direct birefringence modulation. Dynamic alignment of dispersed nanofibers changes the refractive index of the solution and, therefore, the polarization of transmitted light. A reversible reorientation of nanofibers is organized by using a quadrupole configuration of poling electrodes. With further development, the described method can be used in the area of active optical fiber components, lab-on-chip or sensors. It also reveals the potential of 1D conducting polymeric structures as objects whose highly anisotropic properties can be implemented in electro-optical applications..
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