| 1. |
- Zheng, Wenhao, et al.
(författare)
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Dual Function of UV/Ozone Plasma-Treated Polymer in Polymer/Metal Hybrid Electrodes and Semitransparent Polymer Solar Cells
- 2017
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Ingår i: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 9:51, s. 44656-44666
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Tidskriftsartikel (refereegranskat)abstract
- In this work, high-performance inverted indium tin oxide (ITO)-free semitransparent polymer solar cells are comprehensively investigated using a novel polymer/metal hybrid transparent electrode. The electrical and optical characteristics of hybrid electrodes are significantly enhanced by introducing UV/ozone plasma treatment on the polymer poly[(9,9-bis(3-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN), which is functioned as both a seed layer for ultrathin Ag metal electrode and an optical spacer for transparent devices. The optimized sheet resistance of PFN/Ag (12 nm) hybrid electrode is only half of the commercial ITO (9.4 vs 20.0 Omega sq(-1)) and the high wavelength-dependent reflectance of hybrid electrode helps to increase the ITO-free device short-circuit current density. Furthermore, the interface property between PFN and ultrathin Ag is analyzed in detail and the optical field distribution is calculated for comparison. A high power conversion efficiency of 5.02%, which is increased by 35% compared to that of the ITO-based device, is achieved in the ITO-free semitransparent device in conjunction with an excellent average visible transmittance above 28% that is higher than the benchmark of 25% for power-generating window, indicating its great potential in building integrated photovoltaic systems in the future. Furthermore, the strategy is successfully developed for other polymer systems, suggesting the universal applicability for plastic electronics.
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| 2. |
- Hou, Lintao, et al.
(författare)
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Lateral Phase Separation Gradients in Spin-Coated Thin Films of High-Performance Polymer: Fullerene Photovoltaic Blends
- 2011
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Ingår i: Advanced Functional Materials. - : Wiley. - 1616-3028 .- 1616-301X. ; 21:16, s. 3169-3175
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Tidskriftsartikel (refereegranskat)abstract
- In this study, it is demonstrated that a finer nanostructure produced under a rapid rate of solvent removal significantly improves charge separation in a high-performance polymer: fullerene bulk-heterojunction blend. During spin-coating, variations in solvent evaporation rate give rise to lateral phase separation gradients with the degree of coarseness decreasing away from the center of rotation. As a result, across spin-coated thin films the photocurrent at the first interference maximum varies as much as 25%, which is much larger than any optical effect. This is investigated by combining information on the surface morphology of the active layer imaged by atomic force microscopy, the 3D nanostructure imaged by electron tomography, film formation during the spin coating process imaged by optical interference and photocurrent generation distribution in devices imaged by a scanning light pulse technique. The observation that the nanostructure of organic photovoltaic blends can strongly vary across spin-coated thin films will aid the design of solvent mixtures suitable for high molecular-weight polymers and of coating techniques amenable to large area processing.
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| 3. |
- Lin, Yuanbao, et al.
(författare)
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One-Step Blade-Coated Highly Efficient Nonfullerene Organic Solar Cells with a Self-Assembled Interfacial Layer Enabled by Solvent Vapor Annealing
- 2019
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Ingår i: Solar RRL. - : Wiley. - 2367-198X. ; 3:8
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Tidskriftsartikel (refereegranskat)abstract
- A pronounced enhancement of the power conversion efficiency (PCE) by 38% is achieved in one-step doctor-blade printing organic solar cells (OSCs) via a simple solvent vapor annealing (SVA) step. The organic blend composed of a donor polymer, a nonfullerene acceptor, and an interfacial layer (IL) molecular component is found to phase-separate vertically when exposed to a solvent vapor-saturated atmosphere. Remarkably, the spontaneous formation of a fine, self-organized IL between the bulk heterojunction (BHJ) layer and the indium tin oxide (ITO) electrode facilitated by SVA yields solar cells with a significantly higher PCE (11.14%) than in control devices (8.05%) without SVA and in devices (10.06%) made with the more complex two-step doctor-blade printing method. The stratified nature of the ITO/IL/BHJ/cathode is corroborated by a range of complementary characterization techniques including surface energy, cross-sectional scanning electron microscopy, grazing incidence wide angle X-ray scattering, and X-ray photoelectron spectroscopy. This study demonstrates that a spontaneously formed IL with SVA treatment combines simplicity and precision with high device performance, thus making it attractive for large-area manufacturing of next-generation OSCs.
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| 4. |
- Lin, Yuanbao, et al.
(författare)
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Printed Nonfullerene Organic Solar Cells with the Highest Efficiency of 9.5%
- 2018
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Ingår i: Advanced Energy Materials. - : WILEY-V C H VERLAG GMBH. - 1614-6832 .- 1614-6840. ; 8:13
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Tidskriftsartikel (refereegranskat)abstract
- The current work reports a high power conversion efficiency (PCE) of 9.54% achieved with nonfullerene organic solar cells (OSCs) based on PTB7-Th donor and 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2,3-d]-s-indaceno[1,2-b:5,6-b]dithiophene) (ITIC) acceptor fabricated by doctor-blade printing, which has the highest efficiency ever reported in printed nonfullerene OSCs. Furthermore, a high PCE of 7.6% is realized in flexible large-area (2.03 cm(2)) indium tin oxide (ITO)-free doctor-bladed nonfullerene OSCs, which is higher than that (5.86%) of the spin-coated counterpart. To understand the mechanism of the performance enhancement with doctor-blade printing, the morphology, crystallinity, charge recombination, and transport of the active layers are investigated. These results suggest that the good performance of the doctor-blade OSCs is attributed to a favorable nanoscale phase separation by incorporating 0.6 vol% of 1,8-diiodooctane that prolongs the dynamic drying time of the doctor-bladed active layer and contributes to the migration of ITIC molecules in the drying process. High PCE obtained in the flexible large-area ITO-free doctor-bladed nonfullerene OSCs indicates the feasibility of doctor-blade printing in large-scale fullerene-free OSC manufacturing. For the first time, the open-circuit voltage is increased by 0.1 V when 1 vol% solvent additive is added, due to the vertical segregation of ITIC molecules during solvent evaporation.
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| 5. |
- Liu, Alei, et al.
(författare)
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Manipulate Micrometer Surface and Nanometer Bulk Phase Separation Structures in the Active Layer of Organic Solar Cells via Synergy of Ultrasonic and High-Pressure Gas Spraying
- 2019
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Ingår i: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 11:11, s. 10777-10784
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Tidskriftsartikel (refereegranskat)abstract
- For organic solar cells, the vertical and lateral micro-/nanometer-scale structure in the active layer largely determines the device performance. In this work, the surface and bulk domain size of the photoactive layer are successfully manipulated with a facile two-step spraying method, that is, an ultrathin active layer by high-pressure spraying is deliberately stacked on top of the thick active layer by ultrasonic spraying. Thus, the morphology is effectively optimized with the comprehensive study of optical and electrical characteristics, such as photon absorption, exciton dissociation efficiency, and bimolecular recombination. Moreover, the novel method can be used not only in the fullerene system but also in the nonfullerene system, demonstrating the remarkable universality through this synergy method. This work provides an easy and reliable strategy to improve photovoltaic device performance in the industrial large-area spray-coating process.
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| 6. |
- Qin, Leiqiang, et al.
(författare)
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A flexible semitransparent photovoltaic supercapacitor based on water-processed MXene electrodes
- 2020
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry. - 2050-7488 .- 2050-7496. ; 8:11, s. 5467-5475
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Tidskriftsartikel (refereegranskat)abstract
- Solar energy, although it has the highest power density available in terms of renewable energy, has the drawback of being erratic. Integrating an energy harvesting and storage device into photovoltaic energy storage modules is a viable route for obtaining self-powered energy systems. Herein, an MXene-based all-solution processed semitransparent flexible photovoltaic supercapacitor (PSC) was fabricated by integrating a flexible organic photovoltaic (OPV) with Ti3C2Tx MXene as the electrode and transparent MXene supercapacitors with an organic ionogel as the electrolyte in the vertical direction, using Ti3C2Tx thin film as a common electrode. In the quest for a semitransparent flexible PSC, Ti3C2Tx MXene was first used as a transparent electrode for OPV with a high power conversion efficiency of 13.6%. The ionogel electrolyte-based transparent MXene supercapacitor shows a high volumetric capacitance of 502 F cm(-3) and excellent stability. Finally, a flexible PSC with a high average transmittance of over 33.5% was successfully constructed by all-solution processing and a remarkable storage efficiency of 88% was achieved. This strategy enables a simple route for fabricating MXene based high-performance all-solution-processed flexible PSCs, which is important for realizing flexible and printable electronics for future technologies.
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| 7. |
- Qin, Leiqiang, 1987-, et al.
(författare)
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Flexible Solid-State Asymmetric Supercapacitors with Enhanced Performance Enabled by Free-Standing MXene-Biopolymer Nanocomposites and Hierarchical Graphene-RuOx Paper Electrodes
- 2020
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Ingår i: Batteries & Supercaps. - : WILEY-V C H VERLAG GMBH. - 2566-6223. ; 3:7, s. 604-610
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Tidskriftsartikel (refereegranskat)abstract
- Two-dimensional (2D) transition metal carbides and carbonitrides, called MXenes, with metallic conductivity and hydrophilic surfaces, show great promise as electrode materials for supercapacitors. A major drawback of 2D nanomaterials is the re-stacking of the nanosheets, which prevents full utilization of surface area and blocks the access of the electrolyte. In this study, a free-standing nanocomposite paper electrode is realized by combining Mo1.33C MXene and positively charged biopolymer lignin (the second most abundant biopolymer in nature, L-DEA). The self-assembled layered architecture with alternating polymer and MXene flakes increases the interlayer space to promote ion transport, and with combining charge storage capability of the lignin derivative and MXene in an interpenetrating MXene/L-DEA nanocomposite, which offers an impressive capacitance of 503.7 F g(-1). Moreover, we demonstrate flexible solid-state asymmetric supercapacitors (ASCs) using Mo1.33C@L-DEA as the negative electrode and electrochemically exfoliated graphene with ruthenium oxide (EG@RuOx) as the positive electrode. This asymmetric device operates at a voltage window of 1.35 V, which is about two times wider than that of a symmetric Mo1.33C@L-DEA based supercapacitor. Finally, the ASCs can deliver an energy density of 51.9 Wh kg(-1) at a power density of 338.5 W kg(-1), with 86 % capacitance retention after 10000 charge-discharge cycles.
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| 8. |
- Qin, Leiqiang, 1987-, et al.
(författare)
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MXene-based multifunctional smart fibers for wearable and portable electronics
- 2022
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Ingår i: Journal of Materials Chemistry A. - : ROYAL SOC CHEMISTRY. - 2050-7488 .- 2050-7496. ; 10:23, s. 12544-12550
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Tidskriftsartikel (refereegranskat)abstract
- Fiber type devices are promising for applications in wearable and portable electronics. However, scalable fabrication of fiber electrodes with multifunctional performance for use in distinct fields remains challenging. Herein, high performance smart fibers based on Mo1.33C i-MXene nanosheets and poly(3,4-ethylenedioxythiophene):polystyrene sulfonate hybrid paste are fabricated with an easily scalable spinning approach. The hybrid fibers produced by this method can be applied in both high-performance supercapacitors and electrochemical transistors (ECTs). When assembled into a fiber type asymmetric supercapacitor with reduced graphene oxide (rGO) fiber, a capacitance of 105 F g(-1) and an energy density of 37 mW h g(-1) were reached for a potential window of 1.6 V. The hybrid fiber based ECT shows high transconductance and fast response time. This work demonstrates the potential of i-MXene-based fiber electrodes for multifunctional applications, to aid in the development of the next-generation, high-performance wearable electronic devices.
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| 9. |
- Qin, Leiqiang, et al.
(författare)
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Thick Electrodes of a Self-Assembled MXene Hydrogel Composite for High-Rate Energy Storage
- 2023
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Ingår i: ENERGY & ENVIRONMENTAL MATERIALS. - : WILEY. - 2575-0356.
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Tidskriftsartikel (refereegranskat)abstract
- Supercapacitors based on two-dimensional MXene (Ti3C2Tz) have shown extraordinary performance in ultrathin electrodes with low mass loading, but usually there is a significant reduction in high-rate performance as the thickness increases, caused by increasing ion diffusion limitation. Further limitations include restacking of the nanosheets, which makes it challenging to realize the full potential of these electrode materials. Herein, we demonstrate the design of a vertically aligned MXene hydrogel composite, achieved by thermal-assisted self-assembled gelation, for high-rate energy storage. The highly interconnected MXene network in the hydrogel architecture provides very good electron transport properties, and its vertical ion channel structure facilitates rapid ion transport. The resulting hydrogel electrode show excellent performance in both aqueous and organic electrolytes with respect to high capacitance, stability, and high-rate capability for up to 300 mu m thick electrodes, which represents a significant step toward practical applications.
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| 10. |
- Wang, Ergang, 1981, et al.
(författare)
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An Easily Synthesized Blue Polymer for High-Performance Polymer Solar Cells
- 2010
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Ingår i: ADVANCED MATERIALS. - : John Wiley and Sons, Ltd. - 0935-9648 .- 1521-4095. ; 22:46, s. 5240-5244
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Tidskriftsartikel (refereegranskat)abstract
- High performance solar cells fabricated from an easily synthesized donor-acceptor polymer show maximum power point up to 6.0 mW cm(-2), with an open-circuit voltage of 0.89 V, short-circuit current density of 10.5 mA cm(-2) and fill factor of 0.64, making this polymer a particularly promising candidate for high-efficiency low-cost polymer solar cells.
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