| 11. |
- Harillo-Baños, Albert, et al.
(författare)
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High-Throughput Screening of Blade-Coated Polymer:Polymer Solar Cells: Solvent Determines Achievable Performance
- 2022
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Ingår i: ChemSusChem. - : Wiley. - 1864-5631 .- 1864-564X. ; 15:4
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Tidskriftsartikel (refereegranskat)abstract
- Optimization of a new system for organic solar cells is a multiparametric analysis problem that requires substantial efforts in terms of time and resources. The strong microstructure-dependent performance of polymer:polymer cells makes them particularly difficult to optimize, or to translate previous knowledge from spin coating into more scalable techniques. In this work, the photovoltaic performance of blade-coated devices was studied based on the promising polymer:polymer system PBDB-T and PF5-Y5 as donor and acceptor, respectively. Using the recently developed high-throughput methodology, the system was optimized for multiple variables, including solvent system, active layer composition, ratio, and thickness, among others, by fabricating more than 500 devices with less than 24 mg of each component. As a result, the power conversion efficiency of the blade-coated devices varied from 0.08 to 6.43 % in the best device. The performed statistical analysis of the large experimental data obtained showed that solvent selection had the major impact on the final device performance due to its influence on the active layer microstructure. As a conclusion, the use of the plot of the device efficiency in the Hansen space was proposed as a powerful tool to guide solvent selection in organic photovoltaics.
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| 12. |
- Khan, Ziyauddin, et al.
(författare)
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Towards printable water-in-polymer salt electrolytes for high power organic batteries
- 2022
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Ingår i: Journal of Power Sources. - : Elsevier. - 0378-7753 .- 1873-2755. ; 524
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Tidskriftsartikel (refereegranskat)abstract
- Internet-of-things which requires electronics, energy convertor and storage must be low-cost, recyclable and environmentally friendly. In the development of printed batteries, ideally all the components (electrode and electrolyte) must be printable to ensure low-cost manufacturing via printing technologies. Most of the printed batteries suffer with low power. One of the reasons is the poor ionic conductivity of the electrolyte due to the high viscosity needed for printing relatively thick layers. In the present work we have demonstrated a new class of electrolyte promising for printed organic batteries following the concept of water-in-polymer salt electrolytes (WIPSEs). These highly concentrated electrolytes of potassium polyacrylate are non-flammable, low cost and environmentally friendly. They possess high ionic conductivities (45-87 mS/cm) independent on the macroscopic viscosities varying from 7 to 33000 cP. The decoupling between ionic transport and macroscopic viscosity enables us to demonstrate organic batteries based on WIPSEs that can deliver a high and constant power (similar to 4.5 kW/kg; 7.1-11 mW/cm(2)) independent on the viscosity of the electrolytes. The tunability of the viscosity presents a prerequisite for printed technology manufacturing and compatibility with printed batteries.
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| 13. |
- Khan, Ziyauddin, et al.
(författare)
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Water-in-Polymer Salt Electrolyte for Slow Self-Discharge in Organic Batteries
- 2022
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Ingår i: Advanced Energy and Sustainability Research. - : WILEY. - 2699-9412. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- In electrochemical energy storage devices (ESDs), organic electrolytes are typically used for wide operational potential window, yet they suffer with cost, environmental, flammability issues, and low ionic conductivity when compared with water-based electrolytes. Hence, for large-scale applications that require high power and safety, presently there is no true solution. Though water-based electrolytes have higher ionic conductivities, and are cost-effective and nonflammable, their high self-discharge rate with organic/carbon-based electrodes impedes their commercialization. It is found out that highly concentrated polymer electrolytes on the concept of "water-in-salt electrolyte" lead to extremely low leakage current within the electrochemical stability window (ESW) of water, thus solving the issue of self-discharge in organic/carbon-based ESDs. Herein, potassium polyacrylate (PAAK) is prepared as "water-in-polymer salt electrolyte" (WIPSE) and tested for one of most abundant wood-based biopolymer lignin and polyimide as positive and negative electrodes, respectively, in both half-cell and full-cell. The device shows an open-circuit voltage drops <0.45V in 100h setting a record for organic batteries using aqueous electrolyte. The high ionic conductivity (40-120mScm(-1)) nonflammability of PAAK with high ESW (3.1V) opens a new direction for truly safe, sustainable, and high power (6.8kWkg(-1)) organic ESD manufactured by printing technologies.
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| 14. |
- Kim, Jung Yong, et al.
(författare)
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A DNA and Self-Doped Conjugated Polyelectrolyte Assembled for Organic Optoelectronics and Bioelectronics
- 2020
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Ingår i: Biomacromolecules. - : AMER CHEMICAL SOC. - 1525-7797 .- 1526-4602. ; 21:3, s. 1214-1221
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Tidskriftsartikel (refereegranskat)abstract
- Deoxyribonucleic acid (DNA) and a self-doped conjugated polyelectrolyte, poly(4-(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl-methoxy)-1-butanesulfonic acid (PEDOT-S), are assembled for organic optoelectronics and bioelectronics. The DNAs helix-coil phase transition in water is studied as a function of composition by thermo-optical analysis. DNA and PEDOT-S are functionalized by using a surfactant, cetyltrimethylammonium chloride (CTMA), and DNA:CTMA, PEDOT-S:CTMA, and DNA:CTMA:PEDOT-S:CTMA complexes were characterized regarding thermal, optical, morphological, and structural properties. Finally, DNA and DNA:PEDOT-S mixtures are processed in water for fabricating organized films through brushing. The electrical properties of these films are characterized using an interdigitated electrode. The films show an electronic conductivity of similar to 10(-6)-10(-5) S/cm in a range of semiconductors.
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| 15. |
- Kuang, Chaoyang, 1988-
(författare)
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Interface-Assisted Perovskite Modulations for High-Performance Light-Emitting Diodes
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Metal halide perovskites have emerged as a class of promising materials for a wide range of optoelectronic devices. Compared with traditional inorganic and organic semiconductors, perovskite materials can be easily processed via solution-based techniques at low temperatures and exhibit high photo-luminescence efficiency, outstanding colour purity, and superior charge transport properties, showing great promise for cost-effective and high-performance light-emitting diodes (LEDs).Since the first demonstration of room-temperature operating perovskite-based LEDs (PeLEDs) in 2014, various useful strategies on optimizing perovskite emissive materials and device structures have been developed, leading to notably enhanced device performance of PeLEDs during the last several years. Nevertheless, despite rapid progress in improving the external quantum efficiencies (EQEs) of PeLEDs, which are now approaching those of commercialized technologies, the operational stability of state-of-the-art PeLEDs remains poor, presenting a critical challenge for their practical applications and commercialization. Besides, a majority of the optimization strategies demonstrated for PeLEDs derivate from those developed for either perovskite photovoltaics or prevailing light-emitting technologies, e.g., organic- and quantum-dot-based LEDs. Although these strategies are helpful, more comprehensive investigations and in-depth understanding of factors affecting the property of perovskite emissive layers and the device performance of ensuing PeLEDs are highly desirable to foster further advancements of this promising technology.In this thesis, we focus our study on near-infrared PeLEDs based on triiodide perovskite emissive layers processed from precursor solutions. We systematically investigate the critical effects of precursors, substrates, and additives on the film quality of perovskite emissive layers. With the indepth understanding of the perovskite crystallization process, we developed a range of effective interface-assisted strategies on modulating the perovskite emissive layers, which enable us to achieve PeLEDs with high EQEs and excellent long-term operational stability beyond the state-of-the-art.In the first study, we unveiled the synergistic effect of precursor stoichiometry and interfacial reactions for PeLEDs. We reveal that ZnO efficiently deprotonates the organic cations, which promotes the formation of highly emissive perovskites from precursor solution with excess organic components, leading to the achievement of PeLEDs with a high EQE of 19.6 %. In the second study, we presented that such ZnO deprotonation process of excess organic cations can also assist the cation exchange process between cesium-formamidinium (FA-Cs) cation exchange, enabling low-temperature fabrication of pure-phase Cs-FA mixed cation perovskite films with widely tunable emissions peaking between 715 nm and 800 nm as well as high-performance devices with peak EQEs over 15%.In spite of enhanced device efficiency realized by the perovskite crystallization modulation, this ZnO deprotonation process places a detrimental effect on the stability of the PeLEDs, which can be accelerated by Joule heating and high electric fields during the device operation. In the third study, we, therefore, demonstrated the role of ZnO in catalyzing an efficient amidation reaction between incorporated dicarboxylic acid additives and excess FAI, preventing the above-mentioned harmful interfacial reaction. With this strategy, the operational half lifetime of the resulting PeLEDs was improved to 682 hours at 20 mA/cm2 while maintaining a high device efficiency of 18.6%.In the last work, we emphasized that the rational design of molecular reactions between two additives (diamine and triacrylate) and perovskite components with the assistance of ZnO substrates can subsequently eliminate the negative effect introduced by additive, reduce the defect density and enhance the crystal orientation in the perovskite emissive layers. The rational understanding of interfacial interactions between perovskite, additives, and ZnO, enabled us to achieve PeLEDs with a device efficiency of 23.8% as well as an outstanding operational stability T70 (reduction to 70% of initial efficiency) lifetime of 290 hours at 20 mA/cm2.The study in this thesis developed effective interface-assisted modulation strategies for high-quality perovskites towards highly efficient and stable PeLEDs for commercialization. A thorough understanding of perovskite chemistry-property-performance modulation assisted by interfaces is indispensable for the future development of PeLEDs and our study took an important step.
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| 16. |
- Li, Lili, et al.
(författare)
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UV-protection and fluorescence properties of the exoskeleton obtained from a living diatom modified by an Eu3+-complex
- 2021
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Ingår i: Journal of Materials Chemistry C. - : ROYAL SOC CHEMISTRY. - 2050-7526 .- 2050-7534. ; 9:31, s. 10005-10012
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Tidskriftsartikel (refereegranskat)abstract
- In this article, a natural biological porous material, from living diatoms, is used to prepare new UV-protection hybrid materials with an Eu3+-complex. By removing the organic protoplasm of living diatoms, the exoskeleton with a regular pore structure arrangement was obtained. The Eu3+-complex was chemically bonded to the exoskeleton modified by the silane coupling agent (3-aminopropyl)trimethoxy silane (APTMS). Compared with pure Eu3+-complexes, the fluorescence intensity of this hybrid material was increased by approximately 10 times. For illustrating its applications in the field of UV-protection, we mixed the USDU with polyacrylonitrile to produce flexible and transparent polymer films. The hybrid composite film (USDU@PAN) achieved partial absorption of ultraviolet light between 200 and 400 nm. At the same time, it also emits visible fluorescence and the intensity of the fluorescence is greatly increased. Therefore, the USDU@PAN film has wide application prospects in areas such as photoelectric sensors and UV-protection devices. More importantly, we transform natural organisms into materials with excellent optical properties. Therefore, it can be used in the field of UV-protection.
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| 17. |
- Liu, Lianlian, et al.
(författare)
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Bio Based Batteries
- 2021
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Ingår i: Advanced Energy Materials. - : WILEY-V C H VERLAG GMBH. - 1614-6832 .- 1614-6840. ; 11:43
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Tidskriftsartikel (refereegranskat)abstract
- The expanding use of electrical power generated from wind turbines and solar photovoltaic plants is enabled by the decreasing cost of electrical energy from sun and wind. With the advent of electrical energy from the intermittent solar and wind energy resources comes the requirement that electricity must be stored for use over time. The huge demand for materials for such storage systems will require a considerable energy input in extraction, processing and materials formulation, and new and sustainable electrochemical systems need to be developed. Storing electrical energy in bio based batteries is one of the options for handling the rapid expansion of renewable and variable electrical energy generated in wind turbines and in solar photovoltaic systems, from small to large. With projected needs for storage at 300 GWh for the coming decade, there are many niches for new technologies and possibilities. A supply line of materials for energy storage materials could be ultimately based on photosynthesis, in the form of materials derived from plants. Redox activity is possible in lignin, humic acid, and polyphenolic macromolecules, sometimes by electrochemical activation of redox groups.
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| 18. |
- Liu, Lianlian, 1988-, et al.
(författare)
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Black Charcoal for Green and Scalable Wooden Electrodes for Supercapabatteries
- 2022
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Ingår i: Energy Technology. - : Wiley-VCH Verlag GMBH. - 2194-4288 .- 2194-4296. ; 10:3
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Tidskriftsartikel (refereegranskat)abstract
- A green, though black, sustainable and low-cost carbon material-charcoal produced from wood-is developed for electricity storage. Charcoal electrodes are fabricated by ball-milling charcoal and adding protein nanofibril binders. The charcoal electrode presents a capacitance of 360 F g(-1) and a conductivity of 0.2 S m(-1). A pair of redox peaks is observed in the cyclic voltammetry and assigned to originate from quinone groups. Compared with other wooden electrodes, these charcoal electrodes display better cycling stability with 88% capacity retention after 1000 cycles. Their discharge capacity is 2.5 times that of lignosulfonate/graphite hybrid electrodes.
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| 19. |
- Liu, Lianlian, et al.
(författare)
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Quinones from Biopolymers and Small Molecules Milled into Graphite Electrodes
- 2022
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Ingår i: Advanced Materials Technologies. - : Wiley. - 2365-709X. ; 7:2
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Tidskriftsartikel (refereegranskat)abstract
- The redox reactions of quinones can be used in electrical energy storage systems. Biopolymers are one of the important sources for quinones due to sustainability and low cost. In this work, biomass materials that contain a large fraction of potential quinone groups are used to directly fabricate biomass/graphite hybrid material electrodes, without extraction or separation of the redox active components from other elements. Among these biomass electrodes based on barks, the bark from holm oak (Quercus ilex) and graphite hybrid electrode exhibits a discharge capacity of 20 mAh g(-1), with 68% capacity retention after 1000 cycles. Moreover, various quinone chemicals from the biological world are used to generate the quinone/graphite hybrid material electrodes that display higher quinone loadings at the carbon electrodes. The alizarin/graphite hybrid material electrode presents a capacity of 70 mAh g(-1), which is approximate to 30 times higher than that of the graphite electrode. It is demonstrated that barks and quinones are capable of exfoliating graphite into few-layer graphene sheets with reduced crystallite size. Processing into electrodes is facilitated by the use of another biopolymer, proteins in the form of misfolded protein fibrils, which also help to improve the available charge in electrodes formed from biomass or quinones.
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| 20. |
- Liu, Lianlian, 1988-
(författare)
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Renewable and Scalable Energy Storage Materials Derived from Quinones in Biomass
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Currently there is an urgent need to reduce the use of fossil fuels, and efficient sustainable energy harvesters from sun and wind have been developed and are widely used for electricity generation. Storage of electrical energy is accordingly necessary to accommodate the time varying supply of wind and solar electricity. Quinones (Q) are attractive as energy storage materials due to their high theoretical charge density and the renewable and abundant source – biomass. Plant-based biomass materials – such as lignin and humic acids – contain redox active Q-groups that potentially could be used for electricity storage instead of simply burning the biomass, which releases CO2, CH4, NOx, and SOx. Lignin accounts for 20-30% of the biomass weight and contains a sizable fraction of Q-structures. However, utilization of lignin for large scale energy storage is still a challenging task, as lignin is electrically insulating and conductive materials are required to get access to the generated electrons in the bulk. Various relatively expensive materials, such as conductive polymers and various carbon materials (carbon nanotubes, active carbon, graphene, etc.) have been combined with lignin, resulting in hybrid materials for energy storage. However, as the scale required for production of charge storage devices is huge it is of outmost importance to reduce the cost and therefore investigate low-cost conductive materials. In this thesis, common graphite flakes are combined with the lignin derivative lignosulphonate (LS) via a solvent free ball-milling process, followed by treatment with water and resulting in a paste that can be processed into electrodes. Similarly, humic acid derived from peat, lignite that contains a large amount of Q-groups is also fabricated into electrode with graphite via the ball-milling process. In order to further reduce the impact on environment during the extraction of Q-materials from biomass, barks that contain as much as 30% of lignin are directly used for energy storage via co-milling with pristine graphite to generate the biomass/graphite hybrid material electrodes. However, larger weight fraction of Q are required to further improve the electrochemical performance of these electrodes and Q chemicals (QCs) that also originate from biomass are introduced to fabricate the QCs/graphite electrodes with an increased capacity. Additionally, self-discharge mechanism is studied on the LS/graphite hybrid material electrodes, which provides instructions to achieve a low self-discharge rate.Overall, this study has brought us one step forward on the establishing of scalable, sustainable, and cost-effective energy storage systems using aqueous electrolytes.
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