| 1. |
- Abdel Aziz, Ilaria, et al.
(författare)
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Electrochemical modulation of mechanical properties of glycolated polythiophenes
- 2024
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Ingår i: Materials Horizons. - : ROYAL SOC CHEMISTRY. - 2051-6347 .- 2051-6355.
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Tidskriftsartikel (refereegranskat)abstract
- Electrochemical doping of organic mixed ionic-electronic conductors is key for modulating their conductivity, charge storage and volume enabling high performing bioelectronic devices such as recording and stimulating electrodes, transistors-based sensors and actuators. However, electrochemical doping has not been explored to the same extent for modulating the mechanical properties of OMIECs on demand. Here, we report a qualitative and quantitative study on how the mechanical properties of a glycolated polythiophene, p(g3T2), change in situ during electrochemical doping and de-doping. The Young's modulus of p(g3T2) changes from 69 MPa in the dry state to less than 10 MPa in the hydrated state and then further decreases down to 0.4 MPa when electrochemically doped. With electrochemical doping-dedoping the Young's modulus of p(g3T2) changes by more than one order of magnitude reversibly, representing the largest modulation reported for an OMIEC. Furthermore, we show that the electrolyte concentration affects the magnitude of the change, demonstrating that in less concentrated electrolytes more water is driven into the film due to osmosis and therefore the film becomes softer. Finally, we find that the oligo ethylene glycol side chain functionality, specifically the length and asymmetry, affects the extent of modulation. Our findings show that glycolated polythiophenes are promising materials for mechanical actuators with a tunable modulus similar to the range of biological tissues, thus opening a pathway for new mechanostimulation devices. This work investigates the changes in the mechanical properties of glycolated polythiophenes induced by electrochemical addressing and by electrolyte concentration, due to its ability to stabilize water.
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| 2. |
- Admassie, Shimelis, et al.
(författare)
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Biopolymer hybrid electrodes for scalable electricity storage
- 2016
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Ingår i: Materials Horizons. - : ROYAL SOC CHEMISTRY. - 2051-6347 .- 2051-6355. ; 3:3, s. 174-185
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Forskningsöversikt (refereegranskat)abstract
- Powering the future, while maintaining a cleaner environment and a strong socioeconomic growth, is going to be one of the biggest challenges faced by mankind in the 21st century. The first step in overcoming the challenge for a sustainable future is to use energy more efficiently so that the demand for fossil fuels can be reduced drastically. The second step is a transition from the use of fossil fuels to renewable energy sources. In this sense, organic electrode materials are becoming increasingly attractive compared to inorganic electrode materials which have reached a plateau regarding performance and have severe drawbacks in terms of cost, safety and environmental friendliness. Using organic composites based on conducting polymers, such as polypyrrole, and abundant, cheap and naturally occurring biopolymers rich in quinones, such as lignin, has recently emerged as an interesting alternative. These materials, which exhibit electronic and ionic conductivity, provide challenging opportunities in the development of new charge storage materials. This review presents an overview of recent developments in organic biopolymer composite electrodes as renewable electroactive materials towards sustainable, cheap and scalable energy storage devices.
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| 3. |
- Almquist, Ben, et al.
(författare)
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Outstanding Reviewers for Materials Horizons in 2019
- 2020
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Ingår i: Materials Horizons. - : ROYAL SOC CHEMISTRY. - 2051-6347 .- 2051-6355. ; 7:5, s. 1207-1207
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- We would like to take this opportunity to highlight the Outstanding Reviewers for Materials Horizons in 2019, as selected by the editorial team for their significant contribution to the journal.
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| 4. |
- Chen, Junsheng, et al.
(författare)
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Two-photon absorption in halide perovskites and their applications
- 2022
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Ingår i: Materials Horizons. - : Royal Society of Chemistry (RSC). - 2051-6347 .- 2051-6355.
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Tidskriftsartikel (refereegranskat)abstract
- Active research on halide perovskites has given us a deep understanding of this family of materials and their potential for applications in advanced optoelectronic devices. One of the prominent outcomes is the use of perovskite materials for nonlinear optical applications. Two-photon absorption in perovskites, in particular their nanostructures, has been extensively studied and shows huge promise for many applications. However, we are still far from a thorough understanding of two-photon absorption in halide perovskites from a micro to macro perspective. Here we summarize different techniques for studying the two-photon absorption in nonlinear optical materials. We discuss the in-depth photophysics in two-photon absorption in halide perovskites. A comprehensive summary about the factors which influence two-photon absorption provides the direction to improve the two-photon absorption properties of halide perovskites. A summary of the recent applications of two-photon absorption in halide perovskites provides inspirations for engineers to utilize halide perovskites in two-photon absorption device development. This review will help readers to have a comprehensive and in-depth understanding of the research field of two-photon absorption of halide perovskites from microscopic mechanisms to applications. The article can serve as a manual and give inspiration for future researchers.
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| 5. |
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| 6. |
- Dong, Zhiyue, et al.
(författare)
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A cationitrile sequence encodes mild poly(ionic liquid) crosslinking for advanced composite membranes
- 2020
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Ingår i: Materials Horizons. - : Royal Society of Chemistry (RSC). - 2051-6347 .- 2051-6355. ; 7:10, s. 2683-2689
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Tidskriftsartikel (refereegranskat)abstract
- Polymer crosslinking is crucial for the preparation and consolidation of hierarchical nano- and micro-structures, hybrid interfaces, and collective assemblies. Here, for the first time, we showed that a cation-methylene-nitrile (CMN) functionality sequence encoded within repeating units of poly(ionic liquid)s (PILs) allowed for mild cyclizations of nitriles, processes otherwise requiring high temperatures and harsh catalysts. These new reactions facilitated by the CMN sequence were readily translated into freestanding nanomembranes (similar to 19 nm in thickness) and nanocomposite membranes by treating the PILs with mild ammonia vapor (0.2 bar, 20 degrees C). These materials were observed to be stable in various solvents, at different pH levels, and even in boiling water, exhibiting exceptional mechanical strength and solar-thermal desalination performance. The sequence was easy to synthesize, transferable in copolymers, and applicable to various cations, such as imidazolium, pyridinium, and triazolium. We expect it to provide a molecular code promoting programmable polymer crosslinking and the formation of hybrid structures for sustainable energy and water applications.
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| 7. |
- Gluschke, J. G., et al.
(författare)
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Integrated bioelectronic proton-gated logic elements utilizing nanoscale patterned Nafion
- 2021
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Ingår i: Materials Horizons. - : Royal Society of Chemistry (RSC). - 2051-6347 .- 2051-6355. ; 8:1, s. 224-233
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Tidskriftsartikel (refereegranskat)abstract
- A central endeavour in bioelectronics is the development of logic elements to transduce and process ionic to electronic signals. Motivated by this challenge, we report fully monolithic, nanoscale logic elements featuring n- and p-type nanowires as electronic channels that are proton-gated by electron-beam patterned Nafion. We demonstrate inverter circuits with state-of-the-art ion-to-electron transduction performance giving DC gain exceeding 5 and frequency response up to 2 kHz. A key innovation facilitating the logic integration is a new electron-beam process for patterning Nafion with linewidths down to 125 nm. This process delivers feature sizes compatible with low voltage, fast switching elements. This expands the scope for Nafion as a versatile patternable high-proton-conductivity element for bioelectronics and other applications requiring nanoengineered protonic membranes and electrodes.
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| 8. |
- Gond, Ritambhara, et al.
(författare)
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Non-flammable liquid electrolytes for safe batteries
- 2021
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Ingår i: Materials Horizons. - : Royal Society of Chemistry. - 2051-6347 .- 2051-6355. ; 8:11, s. 2913-2928
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Tidskriftsartikel (refereegranskat)abstract
- With continual increments in energy density gradually boosting the performance of rechargeable alkali metal ion (e.g. Li+, Na+, K+) batteries, their safe operation is of growing importance and needs to be considered during their development. This is essential, given the high-profile incidents involving battery fires as portrayed by the media. Such hazardous events result from exothermic chemical reactions occurring between the flammable electrolyte and the electrode material under abusive operating conditions. Some classes of non-flammable organic liquid electrolytes have shown potential towards safer batteries with minimal detrimental effect on cycling and, in some cases, even enhanced performance. This article reviews the state-of-the-art in non-flammable liquid electrolytes for Li-, Na- and K-ion batteries. It provides the reader with an overview of carbonate, ether and phosphate-based organic electrolytes, co-solvated electrolytes and electrolytes with flame-retardant additives as well as highly concentrated and locally highly concentrated electrolytes, ionic liquids and inorganic electrolytes. Furthermore, the functionality and purpose of the components present in typical non-flammable mixtures are discussed. Moreover, many non-flammable liquid electrolytes are shown to offer improved cycling stability and rate capability compared to conventional flammable liquid electrolytes.
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| 9. |
- Gustafsson, Simon, et al.
(författare)
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Mille-feuille paper : a novel type of filter architecture for advanced virus separation applications
- 2016
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Ingår i: Materials Horizons. - Uppsala. - 2051-6347 .- 2051-6355. ; 3:4, s. 320-327
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Tidskriftsartikel (refereegranskat)abstract
- Mille-feuille (“a thousand leaves”) paper is the first non-woven, wet-laid filter paper, composed of 100% native cellulose, which is capable of removal of the “worst-case” model virus, the non-enveloped parvoviruses, i.e. minute virus of mice (MVM; 18–20 nm), from water with a log10 reduction value (LRV) >5 (>99.999%). We further illustrate how the flow rate across the mille-feuille paper can be increased exponentially so that flux rates in the order of 350 L m−2 h−1 bar−1 can be potentially achieved.
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| 10. |
- Hermerschmidt, Felix, et al.
(författare)
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Finally, inkjet-printed metal halide perovskite LEDs-utilizing seed crystal templating of salty PEDOT:PSS
- 2020
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Ingår i: Materials Horizons. - : Royal Society of Chemistry (RSC). - 2051-6347 .- 2051-6355. ; 7:7, s. 1773-1781
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Tidskriftsartikel (refereegranskat)abstract
- Solution-processable metal halide perovskites are increasingly implemented in perovskite-based light-emitting diodes (PeLEDs). Especially green PeLEDs based on methylammonium lead bromide (MAPbBr3) composites exhibit impressive optoelectronic properties, while allowing processing by low-cost and upscalable printing methods. In this study, we have investigated the influence of potassium chloride (KCl) blended into the common hole injection material poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) to boost PeLED device performance. The inclusion of KCl firstly results in a change in morphology of the PEDOT:PSS layer, which then acts as a template during deposition of the perovskite layer. A MAPbBr3:polyethylene glycol (PEG) composite was used, which does not require the deposition of an anti-solvent droplet to induce preferential perovskite crystallization and is therefore suitable for spin coating and scalable inkjet printing processes. PeLEDs utilizing the KCl induced templating effect on a planar PEDOT:PSS/MAPbBr3:PEG architecture show improved performance, predominantly due to improved crystallization. PeLEDs incorporating spin-coated perovskite layers yield a 40-fold increase in luminance (8000 cd m-2) while the turn-on voltage decreases to 2.5 V. KCl-modified PEDOT:PSS contact layers enabled the realization of inkjet-printed PeLEDs with luminance increased by a factor of 20 at a maximum of 4000 cd m-2 and a turn-on voltage of 2.5 V. This work paves the way for inkjet-printed perovskite light-emitting devices for a wide variety of low-cost and customizable applications. This journal is
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| 11. |
- Hong, Jie, et al.
(författare)
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A macroporous carbon nanoframe for hosting Mott-Schottky Fe-Co/Mo2C sites as an outstanding bi-functional oxygen electrocatalyst
- 2023
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Ingår i: Materials Horizons. - : Royal Society of Chemistry. - 2051-6347 .- 2051-6355. ; 10:12, s. 5969-5982
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Tidskriftsartikel (refereegranskat)abstract
- Simultaneously optimizing the d-band center of the catalyst and the mass/charge transport processes during the oxygen catalytic reaction is an essential but arduous task in the pursuit of creating effective and long-lasting bifunctional oxygen catalysts. In this study, a Fe-Co/Mo2C@N-doped carbon macroporous nanoframe was successfully synthesized via a facile “conformal coating and coordination capture” pyrolysis strategy. As expected, the resulting heterogeneous electrocatalyst exhibited excellent reversible oxygen electrocatalytic performance in an alkaline medium, as demonstrated by the small potential gap of 0.635 V between the operating potential of 1.507 V at 10 mA cm−2 for the oxygen evolution reaction and the half-wave potential of 0.872 V towards the oxygen reduction reaction. Additionally, the developed Zn-air battery employing the macroporous nanoframe heterostructure displayed an impressive peak power density of 218 mW cm−2, a noteworthy specific capacity of 694 mA h gZn−1, and remarkable charging/discharging cycle durability. Theoretical calculations confirmed that the built-in electric field between the Fe-Co alloy and Mo2C semiconductor could induce advantageous charge transport and redistribution at the heterointerface, contributing to the optimization of the d-band center of the nanohybrid and ultimately leading to a reduction in the reaction energy barrier during catalytic processes. The exquisite macroporous nanoframe facilitated the rapid transport of ions and charges, as well as the smooth access of oxygen to the internal active site. Thus, the presented unique electronic structure regulation and macroporous structure design show promising potential for the development of robust bifunctional oxygen electrodes.
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| 12. |
- Jin, Handong, et al.
(författare)
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It's a trap! on the nature of localised states and charge trapping in lead halide perovskites
- 2020
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Ingår i: Materials Horizons. - : Royal Society of Chemistry (RSC). - 2051-6347 .- 2051-6355. ; 7:2, s. 397-410
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Forskningsöversikt (refereegranskat)abstract
- The recent surge of scientific interest for lead halide perovskite semiconductors and optoelectronic devices has seen a mix of materials science sub-fields converge on the same "magical" crystal structure. However, this has ultimately shaped some ambiguity in the definitions shared between researchers across different research areas. For example, scientists aiming to decipher the nature of localized states within metal halide perovskites sometimes over simplify the problem, using identifers such as "defects" or "states". Herein, we review the topic of charge carrier trapping within lead halide perovskites, overviewing their causes and influences, as well as specifying their potential resolutions. We assess the popular lead triiodide perovskites for case study and examine the origins of both intrinsic and extrinsic defects leading to charge carrier trapping in performant perovskite-based solar cells, and review the state-of-the-art actions being taken to limit their effects and achieve world-record conversion efficiencies. Finally, we also draw brief comparisons to other emerging lead-free systems and highlight promising optical tools and design principles moving forward.
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| 13. |
- LeCroy, Garrett, et al.
(författare)
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Role of aggregates and microstructure of mixed-ionic-electronic-conductors on charge transport in electrochemical transistors
- 2023
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Ingår i: Materials Horizons. - 2051-6355 .- 2051-6347. ; 10:7, s. 2568-2578
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Tidskriftsartikel (refereegranskat)abstract
- Synthetic efforts have delivered a library of organic mixed ionic-electronic conductors (OMIECs) with high performance in electrochemical transistors. The most promising materials are redox-active conjugated polymers with hydrophilic side chains that reach high transconductances in aqueous electrolytes due to volumetric electrochemical charging. Current approaches to improve transconductance and device stability focus mostly on materials chemistry including backbone and side chain design. However, other parameters such as the initial microstructure and microstructural rearrangements during electrochemical charging are equally important and are influenced by backbone and side chain chemistry. In this study, we employ a polymer system to investigate the fundamental electrochemical charging mechanisms of OMIECs. We couple in situ electronic charge transport measurements and spectroelectrochemistry with ex situ X-ray scattering electrochemical charging experiments and find that polymer chains planarize during electrochemical charging. Our work shows that the most effective conductivity modulation is related to electrochemical accessibility of well-ordered, interconnected aggregates that host high mobility electronic charge carriers. Electrochemical stress cycling induces microstructural changes, but we find that these aggregates can largely maintain order, providing insights on the structural stability and reversibility of electrochemical charging in these systems. This work shows the importance of material design for creating OMIECs that undergo structural rearrangements to accommodate ions and electronic charge carriers during which percolating networks are formed for efficient electronic charge transport.
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| 14. |
- Lin, Yuanbao, et al.
(författare)
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18.73% efficient and stable inverted organic photovoltaics featuring a hybrid hole-extraction layer
- 2023
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Ingår i: Materials Horizons. - : Royal Society of Chemistry (RSC). - 2051-6355 .- 2051-6347. ; 10:4, s. 1292-1300
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Tidskriftsartikel (refereegranskat)abstract
- Developing efficient and stable organic photovoltaics (OPVs) is crucial for the technology's commercial success. However, combining these key attributes remains challenging. Herein, we incorporate the small molecule 2-((3,6-dibromo-9H-carbazol-9-yl)ethyl)phosphonic acid (Br-2PACz) between the bulk-heterojunction (BHJ) and a 7 nm-thin layer of MoO3 in inverted OPVs, and study its effects on the cell performance. We find that the Br-2PACz/MoO3 hole-extraction layer (HEL) boosts the cell's power conversion efficiency (PCE) from 17.36% to 18.73% (uncertified), making them the most efficient inverted OPVs to date. The factors responsible for this improvement include enhanced charge transport, reduced carrier recombination, and favourable vertical phase separation of donor and acceptor components in the BHJ. The Br-2PACz/MoO3-based OPVs exhibit higher operational stability under continuous illumination and thermal annealing (80 degrees C). The T-80 lifetime of OPVs featuring Br-2PACz/MoO3 - taken as the time over which the cell's PCE reduces to 80% of its initial value - increases compared to MoO3-only cells from 297 to 615 h upon illumination and from 731 to 1064 h upon continuous heating. Elemental analysis of the BHJs reveals the enhanced stability to originate from the partially suppressed diffusion of Mo ions into the BHJ and the favourable distribution of the donor and acceptor components induced by the Br-2PACz.
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| 15. |
- Migliaccio, Ludovico, et al.
(författare)
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Aqueous photo(electro)catalysis with eumelanin thin films
- 2018
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Ingår i: Materials Horizons. - : ROYAL SOC CHEMISTRY. - 2051-6347 .- 2051-6355. ; 5:5, s. 984-990
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Tidskriftsartikel (refereegranskat)abstract
- We report that eumelanin, the ubiquitous natural pigment found in most living organisms, is a photocatalytic material. Though the photoconductivity of eumelanin and its photochemical reactions with oxygen have been known for some time, eumelanins have not been regarded as photofaradaic materials. We find that eumelanin shows photocathodic behavior for both the oxygen reduction reaction and the hydrogen evolution reaction. Eumelanin films irradiated in aqueous solutions at pH 2 or 7 with simulated solar light photochemically reduce oxygen to hydrogen peroxide with accompanying oxidation of sacrificial oxalate, formate, or phenol. Autooxidation of the eumelanin competes with the oxidation of donors. Deposition of thin films on electrodes yields photoelectrodes with higher photocatalytic stability compared with the case of pure photocatalysis, implicating the successful extraction of positive charges from the eumelanin layer. These results open up new potential applications for eumelanin as a photocatalytically-active biomaterial, and inform the growing fundamental body of knowledge about the physical chemistry of eumelanins.
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| 16. |
- Moreno, Adrian, et al.
(författare)
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Lignin-based smart materials : a roadmap to processing and synthesis for current and future applications
- 2020
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Ingår i: Materials Horizons. - : Royal Society of Chemistry (RSC). - 2051-6347 .- 2051-6355. ; 7:9, s. 2237-2257
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Forskningsöversikt (refereegranskat)abstract
- Biomass-derived materials are green alternatives to synthetic plastics and other fossil-based materials. Lignin, an aromatic plant polymer, is one of the most appealing renewable material precursors for smart materials capable of responding to different stimuli. Here we review lignin-based smart materials, a research field that has seen a rapid growth during the last five years. We describe the main processing and chemical synthesis routes available for the fabrication of lignin-based smart materials, and focus on their use as sensors, biomedical systems, and shape-programmable materials. In addition to benchmarking their performance to the state of the art fossil counterparts, we identify challenges and future opportunities for the development of lignin-based smart materials towards new high-performance applications.
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| 17. |
- Norrbo, Isabella, et al.
(författare)
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Solar UV index and UV dose determination with photochromic hackmanites : from the assessment of the fundamental properties to the device
- 2018
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Ingår i: Materials Horizons. - : Royal Society of Chemistry (RSC). - 2051-6347 .- 2051-6355. ; 5:3, s. 569-576
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Tidskriftsartikel (refereegranskat)abstract
- Extended exposure to sunlight or artificial UV sources is a major cause of serious skin and eye diseases such as cancer. There is thus a great need for convenient materials for the easy monitoring of UV doses. While organic photochromic molecules are tunable for responses under different wavelengths of UV radiation, they suffer from rather poor durability because the color changes involve drastic changes in molecular structure. Inorganic materials, on the other hand, are durable, but they have lacked tunability. Here, by combining computational and empirical data, we confirm the mechanism of coloration in the hackmanites, nature-based materials, and introduce a new technique called thermotenebrescence. With knowledge of the mechanism, we show that we can control and thus tune the energy of electronic states of synthetic hackmanites (Na,M)(8)Al6Si6O24(Cl,S)(2) so that their body color is sensitive to the solar UV index as well as UVA, UVB or UVC radiation levels. Finally, we demonstrate that it is possible to use images taken with an inexpensive cell phone to quantify the radiation dose or UV index. The hackmanite materials thus show great potential for use in portable healthcare both in everyday life and in laboratories.
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| 18. |
- Pampel, J., et al.
(författare)
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Ionothermal template transformations for preparation of tubular porous nitrogen doped carbons
- 2017
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Ingår i: Materials Horizons. - : Royal Society of Chemistry (RSC). - 2051-6347 .- 2051-6355. ; 4:3, s. 493-501
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Tidskriftsartikel (refereegranskat)abstract
- A facile approach for the Zn-free ionothermal synthesis of highly porous nitrogen doped carbons possessing tubular transport pores is demonstrated employing adenine as biomass derived precursor and surfactant together with calcium or magnesium chloride hydrates as combined solvent-porogens. The overall process can be regarded as a combination of liquid templating by means of sol-gel synthesis with hard templating via in situ transformation of the melt into solid fibrous salt crystals. The employment of MgCl2 center dot 6H(2)O results in tubular nitrogen doped carbons showing anisotropic porosity and very high specific surface areas up to 2780 m(2) g(-1) and total pore volumes up to 3.86 cm(3) g(-1). The formation of the tubular porosity can be connected to a cooperative effect between in situ formed, solid hydrate phases and their modulation with adenine and its polycondensation products. The combination of high SSA with the channel-like porosity generates a highly accessible structure making those carbon materials appealing for applications that demand good mass transport. The obtained materials were exemplarily employed as supercapacitor electrodes resulting in high specific capacitances up to 238 F g(-1) at a low scan rate of 2 mV s(-1) and up to 144 F g(-1) at a high scan rate of 200 mV s(-1).
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| 19. |
- Parker, Daniela, et al.
(författare)
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Biohybrid plants with electronic roots via in vivo polymerization of conjugated oligomers
- 2021
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Ingår i: Materials Horizons. - : Royal Society of Chemistry. - 2051-6347 .- 2051-6355. ; 8:12, s. 3295-3305
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Tidskriftsartikel (refereegranskat)abstract
- Plant processes, ranging from photosynthesis through production of biomaterials to environmental sensing and adaptation, can be used in technology via integration of functional materials and devices. Previously, plants with integrated organic electronic devices and circuits distributed in their vascular tissue and organs have been demonstrated. To circumvent biological barriers, and thereby access the internal tissue, plant cuttings were used, which resulted in biohybrids with limited lifetime and use. Here, we report intact plants with electronic functionality that continue to grow and develop enabling plant-biohybrid systems that fully maintain their biological processes. The biocatalytic machinery of the plant cell wall was leveraged to seamlessly integrate conductors with mixed ionic-electronic conductivity along the root system of the plants. Cell wall peroxidases catalyzed ETE-S polymerization while the plant tissue served as the template, organizing the polymer in a favorable manner. The conductivity of the resulting p(ETE-S) roots reached the order of 10 S cm(-1) and remained stable over the course of 4 weeks while the roots continued to grow. The p(ETE-S) roots were used to build supercapacitors that outperform previous plant-biohybrid charge storage demonstrations. Plants were not affected by the electronic functionalization but adapted to this new hybrid state by developing a more complex root system. Biohybrid plants with electronic roots pave the way for autonomous systems with potential applications in energy, sensing and robotics.
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| 20. |
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| 21. |
- Pineider, F., et al.
(författare)
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Plasmon-enhanced magneto-optical detection of single-molecule magnets
- 2019
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Ingår i: Materials Horizons. - : Royal Society of Chemistry (RSC). - 2051-6347 .- 2051-6355. ; 6:6, s. 1148-1155
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Tidskriftsartikel (refereegranskat)abstract
- Here we report on nanoarchitectures composed of molecular magnets deposited on optical nanoantennas. We demonstrate a significantly boosted magneto-optical detection of a thin film of a terbium(III) bis-phthalocianinato (TbPc2) single-molecule magnet and we track down the origin of this enhancement to nanoantenna effects at the optical level. This finding suggests that the vast knowledge on plasmon-enhanced spectroscopies can be readily extended to magneto-optics, thus paving the way to strong magneto-optical enhancements for the readout of nanometric devices embedding single-molecule magnets.
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| 22. |
- Qin, Jiajun, et al.
(författare)
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From optical pumping to electrical pumping: the threshold overestimation in metal halide perovskites
- 2023
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Ingår i: Materials Horizons. - : ROYAL SOC CHEMISTRY. - 2051-6347 .- 2051-6355. ; 10:4, s. 1446-1453
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Tidskriftsartikel (refereegranskat)abstract
- The threshold carrier density, conventionally evaluated from optical pumping, is a key reference parameter towards electrically pumped lasers with the widely acknowledged assumption that optically excited charge carriers relax to the band edge through an ultrafast process. However, the characteristically slow carrier cooling in perovskites challenges this assumption. Here, we investigate the optical pumping of state-of-the-art bromide- and iodine-based perovskites. We find that the threshold decreases by one order of magnitude with decreasing excitation energy from 3.10 eV to 2.48 eV for methylammonium lead bromide perovskite (MAPbBr(3)), indicating that the low-energy photon excitation facilitates faster cooling and hence enables efficient carrier accumulation for population inversion. Our results are then interpreted due to the coupling of phonon scattering in connection with the band structure of perovskites. This effect is further verified in the two-photon pumping process, where the carriers relax to the band edge with a smaller difference in phonon momentum that speeds up the carrier cooling process. Furthermore, by extrapolating the optical pumping threshold to the band edge excitation as an analog of the electrical carrier injection to the perovskite, we obtain a critical threshold carrier density of similar to 1.9 x 10(17) cm(-3), which is one order of magnitude lower than that estimated from the conventional approach. Our work thus highlights the feasibility of metal halide perovskites for electrically pumped lasers.
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| 23. |
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| 24. |
- Sun, Pengliang, et al.
(författare)
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Treasure-bowl style bifunctional site in cerium-tungsten hetero-clusters for superior solar-driven hydrogen production
- 2024
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Ingår i: Materials Horizons. - : Royal Society of Chemistry. - 2051-6347 .- 2051-6355.
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Tidskriftsartikel (refereegranskat)abstract
- Electrochemical water splitting powered by renewable energy sources hold potential for clean hydrogen production. However, there is still persistent challenges such as low solar-to-hydrogen conversion efficiency and sluggish oxygen evolution reactions. Here, we address the poor kinetics by studying and strengthening the coupling between Ce and W, and concurrently establishing Ce-W bi-atomic clusters on P,N-doped carbon (WN/WC-CeO2−x@PNC) with a “treasure-bowl” style. The bifunctional active sites are established using a novel and effective self-sacrificial strategy involving in situ induced defect formation. In addition, by altering the coupling of the W(d)-N(p) and W(d)-Ce(f) orbitals in the WN/WC-CeO2−x supramolecular clusters, we are able to disrupt the linear relationship between the binding energies of reaction intermediates, a key to obtain high catalytic performance for transition metals. Through the confinement of the WN/WC-CeO2−x composite hetero-clusters within the sub-nanometre spaces of hollow nano-bowl-shaped carbon reactors, a stable and efficient hydrogen production via water electrolysis could be achieved. When assembled together with a solar GaAs triple junction solar cell, a solar-to-hydrogen conversion efficiency of 18.92% in alkaline media could be realized. We show that the key to establish noble metal free catalysts with high efficiency lies in the fine-tuning of the metal-metal interface, forming regions with near optimal adsorption energies for the reaction intermediates participating in water electrolysis.
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| 25. |
- Szlachetko, Jakub, et al.
(författare)
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Hidden gapless states during thermal transformations of preorganized zinc alkoxides to zinc oxide nanocrystals
- 2018
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Ingår i: Materials Horizons. - : Royal Society of Chemistry (RSC). - 2051-6347 .- 2051-6355. ; 5:5, s. 905-911
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Tidskriftsartikel (refereegranskat)abstract
- Zinc oxide (ZnO) is one of the most versatile semiconductor materials with multifarious potential applications. Easily accessible alkylzinc alkoxides have been widely exploited as single-source precursors of ZnO-based nanomaterials but their multi-step decomposition pathways have not been understood in detail. Herein, the formation mechanism of ZnO nanocrystals via solid-state thermal decomposition of a model pre-organised alkylzinc alkoxide precursor, i.e. [tBuZn(mu(3)-OtBu)](4), is elucidated using in situ valence-to-core X-ray emission (v2c-XES) and high energy resolution off-resonant spectroscopy (HEROS) in conjunction with theoretical calculations. Combination of in situ spectroscopic measurements and theoretical simulations indicates that the precursor structural evolution is initiated by the homolytic cleavage of the R-Zn bond, which leads to the formation of a transient radical ([center dot Zn(mu(3)-OR)][RZn(mu(3)-OR)](3)) species, which is responsible for the initial decomposition process. The ensuing multistep transformations involve the formation of intermediate radical zinc oxo-alkoxide clusters with gapless electronic states. Hitherto, the formation of clusters of this type has not been considered either as intermediate structures en route to a semiconductor ZnO phase or as potential species accounting for various defect states of ZnO NCs, particularly the singly charged oxygen vacancy, V-o(+).
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| 26. |
- Tallia, F, et al.
(författare)
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Bouncing and 3D printable hybrids with self-healing properties
- 2018
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Ingår i: MATERIALS HORIZONS. - : Royal Society of Chemistry (RSC). - 2051-6347 .- 2051-6355. ; 5:5, s. 849-860
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Novel sol–gel hybrid materials that put bounce in bioactive glass, can self-heal and can be directly 3D printed.
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| 27. |
- Urbanaviciute, Indre, 1990-, et al.
(författare)
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Negative piezoelectric effect in an organic supramolecular ferroelectric
- 2019
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Ingår i: Materials Horizons. - : Royal Society of Chemistry. - 2051-6347 .- 2051-6355. ; 6, s. 1688-1698
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Tidskriftsartikel (refereegranskat)abstract
- The vast majority of ferroelectric materials demonstrate a positive piezoelectric effect. Theoretically, the negative piezoelectric coefficient d33 could be found in certain classes of ferroelectrics, yet in practice, the number of materials showing linear longitudinal contraction with increasing applied field (d33 < 0) is limited to few ferroelectric polymers. Here, we measure a pronounced negative piezoelectric effect in the family of organic ferroelectric small-molecular BTAs (trialkylbenzene-1,3,5-tricarboxamides), which can be tuned by mesogenic tail substitution and structural disorder. While the large- and small-signal strain in highly-ordered thin-film BTA capacitor devices are dominated by intrinsic contributions and originates from piezostriction, rising disorder introduces additional extrinsic factors that boost the large-signal d33 up to −20 pm V-ˆ’1 in short-tailed molecules. Interestingly, homologues with longer mesogenic tails show a large-signal electromechanical response that is dominated by the quadratic Maxwell strain with significant mechanical softening upon polarization switching, whereas the small-signal strain remains piezostrictive. Molecular dynamics and DFT calculations both predict a positive d33 for defect-free BTA stacks. Hence, the measured negative macroscopic d33 is attributed to the presence of structural defects that enable the dimensional effect to dominate the piezoelectric response of BTA thin films.
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| 28. |
- Urbanaviciute, Indre, et al.
(författare)
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Negative piezoelectric effect in an organic supramolecular ferroelectric
- 2019
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Ingår i: Materials Horizons. - : Royal Society of Chemistry (RSC). - 2051-6347 .- 2051-6355. ; 6:8, s. 1688-1698
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Tidskriftsartikel (refereegranskat)abstract
- The vast majority of ferroelectric materials demonstrate a positive piezoelectric effect. Theoretically, the negative piezoelectric coefficient d(33) could be found in certain classes of ferroelectrics, yet in practice, the number of materials showing linear longitudinal contraction with increasing applied field (d(33) < 0) is limited to few ferroelectric polymers. Here, we measure a pronounced negative piezoelectric effect in the family of organic ferroelectric small-molecular BTAs (trialkylbenzene-1,3,5-tricarboxamides), which can be tuned by mesogenic tail substitution and structural disorder. While the large- and small-signal strain in highly-ordered thin-film BTA capacitor devices are dominated by intrinsic contributions and originates from piezostriction, rising disorder introduces additional extrinsic factors that boost the large-signal d(33) up to -20 pm V-1 in short-tailed molecules. Interestingly, homologues with longer mesogenic tails show a large-signal electromechanical response that is dominated by the quadratic Maxwell strain with significant mechanical softening upon polarization switching, whereas the small-signal strain remains piezostrictive. Molecular dynamics and DFT calculations both predict a positive d(33) for defect-free BTA stacks. Hence, the measured negative macroscopic d(33) is attributed to the presence of structural defects that enable the dimensional effect to dominate the piezoelectric response of BTA thin films.
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| 29. |
- Wang, Kuan, et al.
(författare)
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Threshold switching memristor-based stochastic neurons for probabilistic computing
- 2021
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Ingår i: Materials Horizons. - : Royal Society of Chemistry. - 2051-6347 .- 2051-6355. ; 8:2, s. 619-629
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Tidskriftsartikel (refereegranskat)abstract
- Biological neurons exhibit dynamic excitation behavior in the form of stochastic firing, rather than stiffly giving out spikes upon reaching a fixed threshold voltage, which empowers the brain to perform probabilistic inference in the face of uncertainty. However, owing to the complexity of the stochastic firing process in biological neurons, the challenge of fabricating and applying stochastic neurons with bio-realistic dynamics to probabilistic scenarios remains to be fully addressed. In this work, a novel CuS/GeSe conductive-bridge threshold switching memristor is fabricated and singled out to realize electronic stochastic neurons, which is ascribed to the similarity between the stochastic switching behavior observed in the device and that of biological ion channels. The corresponding electric circuit of a stochastic neuron is then constructed and the probabilistic firing capacity of the neuron is utilized to implement Bayesian inference in a spiking neural network (SNN). The application prospects are demonstrated on the example of a tumor diagnosis task, where common fatal diagnostic errors of a conventional artificial neural network are successfully circumvented. Moreover, in comparison to deterministic neuron-based SNNs, the stochastic neurons enable SNNs to deliver an estimate of the uncertainty in their predictions, and the fidelity of the judgement is drastically improved by 81.2%.
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| 30. |
- Wu, Hanyan, et al.
(författare)
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Stable organic electrochemical neurons based on p-type and n-type ladder polymers
- 2023
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Ingår i: Materials Horizons. - : ROYAL SOC CHEMISTRY. - 2051-6347 .- 2051-6355. ; :10, s. 4213-4223
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Tidskriftsartikel (refereegranskat)abstract
- Organic electrochemical transistors (OECTs) are a rapidly advancing technology that plays a crucial role in the development of next-generation bioelectronic devices. Recent advances in p-type/n-type organic mixed ionic-electronic conductors (OMIECs) have enabled power-efficient complementary OECT technologies for various applications, such as chemical/biological sensing, large-scale logic gates, and neuromorphic computing. However, ensuring long-term operational stability remains a significant challenge that hinders their widespread adoption. While p-type OMIECs are generally more stable than n-type OMIECs, they still face limitations, especially during prolonged operations. Here, we demonstrate that simple methylation of the pyrrole-benzothiazine-based (PBBT) ladder polymer backbone results in stable and high-performance p-type OECTs. The methylated PBBT (PBBT-Me) exhibits a 25-fold increase in OECT mobility and an impressive 36-fold increase in & mu;C* (mobility x volumetric capacitance) compared to the non-methylated PBBT-H polymer. Combining the newly developed PBBT-Me with the ladder n-type poly(benzimidazobenzophenanthroline) (BBL), we developed complementary inverters with a record-high DC gain of 194 V V-1 and excellent stability. These state-of-the-art complementary inverters were used to demonstrate leaky integrate-and-fire type organic electrochemical neurons (LIF-OECNs) capable of biologically relevant firing frequencies of about 2 Hz and of operating continuously for up to 6.5 h. This achievement represents a significant improvement over previous results and holds great potential for developing stable bioelectronic circuits capable of in-sensor computing.
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| 31. |
- Wu, Yue, et al.
(författare)
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Photoswitching between black and colourless spectra exhibits resettable spatiotemporal logic
- 2016
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Ingår i: Materials Horizons. - : Royal Society of Chemistry. - 2051-6347 .- 2051-6355. ; 3:2, s. 124-129
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Tidskriftsartikel (refereegranskat)abstract
- Logic is the key to computing. Traditionally, logic devices have been fabricated by the top-down approach, whose dimensions are drastically limited. The ultimate goal is to use molecular tailorability to design logics using the "bottom-up'' approach. Here we report an unprecedented photochromic molecule that undergoes unimolecular logic switching when excited anywhere in the entire UV-visible spectrum, thus a bottom-up, all-photonic, molecular logic gate. Specifically, these molecular photonic logics embedded in the polymer thin films function as the "AND'' or "OR'' gate at different temporal responses. To achieve high information-processing density, moreover, a ternary flip-flap-flop gate is realized in the molecular logic because the fact that this photochromic molecule can be photoswitched anywhere in its UV-vis spectrum enabled three different lasers (532, 473, and 561 nm) as the inputs to deliver the complex logic optical outputs.
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| 32. |
- Xu, Weidong, 1988-, et al.
(författare)
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The progress and prospects of non-fullerene acceptors in ternary blend organic solar cells
- 2018
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Ingår i: Materials Horizons. - : ROYAL SOC CHEMISTRY. - 2051-6347 .- 2051-6355. ; 5:2, s. 206-221
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Forskningsöversikt (refereegranskat)abstract
- The rapid development of organic solar cells (OSCs) based on non-fullerene acceptors has attracted increasing attention during the past few years, with a record power conversion efficiency of over 13% in a binary bulk heterojunction architecture. This exciting development also enables new possibilities for ternary OSCs to further enhance their efficiency and stability. This review summarizes very recent developments of ternary OSCs, with a focus on blends involving non-fullerene acceptors. We also highlight the challenges and perspectives for further development of ternary blend organic solar cells.
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| 33. |
- Zhou, Shengyang, et al.
(författare)
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A mechanically robust spiral fiber with ionic-electronic coupling for multimodal energy harvesting
- 2024
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Ingår i: Materials Horizons. - : ROYAL SOC CHEMISTRY. - 2051-6347 .- 2051-6355.
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Tidskriftsartikel (refereegranskat)abstract
- Wearable electronics are some of the most promising technologies with the potential to transform many aspects of human life such as smart healthcare and intelligent communication. The design of self-powered fabrics with the ability to efficiently harvest energy from the ambient environment would not only be beneficial for their integration with textiles, but would also reduce the environmental impact of wearable technologies by eliminating their need for disposable batteries. Herein, inspired by classical Archimedean spirals, we report a metastructured fiber fabricated by scrolling followed by cold drawing of a bilayer thin film of an MXene and a solid polymer electrolyte. The obtained composite fibers with a typical spiral metastructure (SMFs) exhibit high efficiency for dispersing external stress, resulting in simultaneously high specific mechanical strength and toughness. Furthermore, the alternating layers of the MXene and polymer electrolyte form a unique, tandem ionic-electronic coupling device, enabling SMFs to generate electricity from diverse environmental parameters, such as mechanical vibrations, moisture gradients, and temperature differences. This work presents a design rule for assembling planar architectures into robust fibrous metastructures, and introduces the concept of ionic-electronic coupling fibers for efficient multimodal energy harvesting, which have great potential in the field of self-powered wearable electronics. In this work, a concept of ionic-electronic coupling fibers by integrating a 2D MXene and a polymer electrolyte to fabricate spiral metastructures is proposed to realize multimodal power generation from various sources simultaneously.
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| 34. |
- Zokaei, Sepideh, 1991, et al.
(författare)
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Tuning of the elastic modulus of a soft polythiophene through molecular doping
- 2022
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Ingår i: Materials Horizons. - : Royal Society of Chemistry (RSC). - 2051-6355 .- 2051-6347. ; 9:1, s. 433-443
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Tidskriftsartikel (refereegranskat)abstract
- Molecular doping of a polythiophene with oligoethylene glycol side chains is found to strongly modulate not only the electrical but also the mechanical properties of the polymer. An oxidation level of up to 18% results in an electrical conductivity of more than 52 S cm(-1) and at the same time significantly enhances the elastic modulus from 8 to more than 200 MPa and toughness from 0.5 to 5.1 MJ m(-3). These changes arise because molecular doping strongly influences the glass transition temperature T-g and the degree of pi-stacking of the polymer, as indicated by both X-ray diffraction and molecular dynamics simulations. Surprisingly, a comparison of doped materials containing mono- or dianions reveals that - for a comparable oxidation level - the presence of multivalent counterions has little effect on the stiffness. Evidently, molecular doping is a powerful tool that can be used for the design of mechanically robust conducting materials, which may find use within the field of flexible and stretchable electronics.
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| 35. |
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| 36. |
- Schröder, Vincent R.F., et al.
(författare)
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Bicolour, large area, inkjet-printed metal halide perovskite light emitting diodes
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Ingår i: Materials Horizons. - 2051-6347.
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate a bicoloured metal halide perovskite (MHP) light emitting diode (LED) fabricated in two sequential inkjet printing steps. By adjusting the printing parameters, we selectively and deliberately redissolve and recrystallize the first printed emissive layer to add a pattern emitting in a different color. The red light emitting features (on a green light emitting background) have a minimum size of 100 μm and originate from iodide-rich domains in a phase-segregated, mixed MHP. This phase forms between the first layer, a bromide-based MHP, which is partially dissolved by printing, and the second layer, an iodide-containing MHP. With an optimised printing process we can retain the active layer integrity and fabricate bicolour, large area MHP-based LEDs with up to 1600 mm2 active area. The two emission peaks at 535 nm and 710 nm are well separated and produce a strong visual contrast.
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