| 1. |
- Aderne, Rian E., et al.
(författare)
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On the energy gap determination of organic optoelectronic materials : the case of porphyrin derivatives
- 2022
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Ingår i: Materials Advances. - : Royal Society of Chemistry. - 2633-5409. ; :3, s. 1791-1803
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Tidskriftsartikel (refereegranskat)abstract
- The correct determination of the ionization potential (IP) and electron affinity (EA) as well as the energy gap is essential to properly characterize a series of key phenomena related to the applications of organic semiconductors. For example, energy offsets play an essential role in charge separation in organic photovoltaics. Yet there has been a lot of confusion involving the real physical meaning behind those quantities. Experimentally the energy gap can be measured by direct techniques such as UV-Vis absorption, or indirect techniques such as cyclic voltammetry (CV). Another spectroscopic method is the Reflection Electron Energy Loss Spectroscopy (REELS). Regarding data correlation, there is little consensus on how the REELS' energy gap can be interpreted in light of the energies obtained from other methodologies such as CV, UV-Vis, or photoemission. In addition, even data acquired using those traditional techniques has been misinterpreted or applied to derive conclusions beyond the limits imposed by the physics of the measurement. A similar situation also happens when different theoretical approaches are used to assess the energy gap or employed to explain outcomes from experiments. By using a set of porphyrin derivatives as model molecules, we discuss some key aspects of those important issues. The peculiar properties of these porphyrins demonstrate that even straightforward measurements or calculations performed in a group of very similar molecules need a careful interpretation of the outcomes. Differences up to 660 meV (similar to 190 meV) are found comparing REELS (electrochemical) measurements with UV-Vis energy gaps, for instance. From the theoretical point of view, a reasonable agreement with electrochemical measurements of the IP, EA, and the gap of the porphyrins is only obtained when the calculations involve the full thermodynamics of the redox processes. The purpose of this work is to shed light on the differences and similarities of those aforementioned characterization methods and provide some insight that might help one to develop a critical analysis of the different experimental and theoretical methodologies.
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| 2. |
- Allushi, Andrit, et al.
(författare)
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Hydroxide conducting BAB triblock copolymers tailored for durable high-performance anion exchange membranes
- 2023
-
Ingår i: Materials Advances. - 2633-5409. ; 4:17, s. 3733-3745
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Tidskriftsartikel (refereegranskat)abstract
- Well-designed block copolymers with a controlled co-continuous microphase morphology can be applied as efficient anion exchange membranes (AEMs) for fuel cells and water electrolyzers. In the present work, we have prepared and studied a series of BAB triblock copolymers consisting of a central cationic polyfluorene A block with flanking hydrophobic polystyrene B blocks, where the fluorene units of the A block carried double pairs of piperidinium cations via flexible hexyl spacer chains. First, a polyfluorene tethered with bromohexyl chains was prepared by superacid-mediated polyhydroxyalkylation, and then modified to produce a bi-directional macroinitiator for atom transfer radical polymerization (ATRP). Next, ATRP of styrene was carried out to form BAB triblock copolymers with different lengths of the B blocks. Finally, the polyfluorene block was densely functionalized with piperidinium cations by Menshutkin reactions. Small angle X-ray scattering of block copolymer AEMs indicated the presence of both block copolymer phase domains (d~15 nm) and ionic clusters (d~6 nm). Atomic force microscopy showed clearly phase-separated morphologies with seemingly well-connected hydrophilic nanophase domains for ion transport. The AEMs reached hydroxide conductivities up to 161 mS cm-1 at 80 ºC. Moreover, the AEMs decomposed only above 250 °C and possessed excellent alkaline stability with no degradation detected by 1H NMR analysis after storage in 2 M aq. NaOH, at 90 °C during 672 h. Notably, the current block copolymer AEMs showed higher alkaline stability and hydroxide conductivity compared to AEMs based on corresponding statistical copolymers.
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| 3. |
- Banerjee, Shrobona, et al.
(författare)
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Porous aluminum decorated with rhodium nanoparticles : preparation and use as a platform for UV SERS
- 2024
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Ingår i: Materials Advances. - : Royal Society of Chemistry. - 2633-5409.
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Tidskriftsartikel (refereegranskat)abstract
- Currently, there is a high interest in novel plasmonic platforms and materials able to extend their applicability into the ultraviolet (UV) region of the electromagnetic spectrum. In the UV it is possible to explore the spectral properties of biomolecules that have only a small cross-section in the visible spectral range. However, most plasmonic metals have their resonances at wavelengths >350 nm. Aluminum and rhodium are two exceptions and therefore interesting candidate materials for UV plasmonics. In this work we developed a simple and low-cost preparation of functional substrates based on nanoporous aluminum decorated with rhodium nanoparticles. We demonstrate that these functionalized nanoporous metal films can be exploited as plasmonic materials for enhanced UV Raman spectroscopy.
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| 4. |
- Bartkowska, Aleksandra, et al.
(författare)
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Biodegradable porous FeMn(-xAg) alloys: assessment of cytocompatibility, mechanical, magnetic and antibiofilm properties
- 2023
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Ingår i: Materials Advances. - : Royal Society of Chemistry (RSC). - 2633-5409. ; 4:2, s. 616-630
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Tidskriftsartikel (refereegranskat)abstract
- In this work, porous FeMn(-xAg) alloys are fabricated through powder metallurgy methods. The effects of porosity and Ag addition on the microstructure, biodegradability, magnetic and mechanical properties of the alloys are investigated. Studies on the cytocompatibility, inflammatory cytokine response and antibacterial effect are also conducted. The fabricated alloys exhibit a macro- and nanoporous structure, with uniformly distributed silver particles. The biodegradability tests reveal that the release of Mn to the Hank's solution is higher than that of Fe, without significant differences between the alloys. The degradation products consist mainly of Fe, Mn, O and compounds enriched in Ca, P and Cl. As-sintered alloys show a low saturation magnetization value (below 1 emu g−1), which does not increase significantly with immersion time. The results on biocompatibility indicate that all tested alloys are non-cytotoxic, but the addition of Ag might interfere with cell proliferation. However, the ions released by the FeMn(-xAg) alloys do not induce an inflammatory response in macrophages. The obtained results on microbiological interactions reveal that although no significant bactericidal effect is observed at 4 h between FeMn control and FeMn-5Ag, a significant reduction in the total biofilm biomass of both live and dead bacteria is observed after 24 h in Ag containing FeMn-5Ag surfaces.
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| 5. |
- Birdsong, Björn K., et al.
(författare)
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Flexible and fire-retardant silica/cellulose aerogel using bacterial cellulose nanofibrils as template material
- 2024
-
Ingår i: Materials Advances. - : Royal Society of Chemistry. - 2633-5409. ; 5:12, s. 5041-5051
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Tidskriftsartikel (refereegranskat)abstract
- This study explores the possibility of using various silsesquioxane precursors such as (3-aminopropyl) triethoxysilane (APTES), methyltrimethoxysilane (MTMS), and tetraethyl orthosilicate (TEOS) to produce silsesquioxane-bacterial cellulose nanofibre (bCNF) aerogels. Each precursor allowed to customize the aerogel properties, leading to unique properties suitable for various applications requiring lightweight insulative materials. When utilizing APTES as the silsesquioxane precursor, an aerogel capable of over 90% recovery after compression was formed, making them suitable for flexible applications. When MTMS was used as the precursor, the aerogel retained some compression recovery (80%) but had the added property of superhydrophobicity with a contact angle over 160° due to the presence of CH3 functional groups, enabling water-repellence. Finally, TEOS allowed for excellent thermal insulative properties with a low Peak Heat Release Rate (PHRR), making it a promising candidate for fire-resistant applications. The customization of these aerogel materials was attributed to a combination of the chemical composition of the silsesquioxane precursors and the morphology of the coated bacterial cellulose nanofibres (bCNF), such as CH3 groups found in MTMS enabled for superhydrophobicity. Differences in morphology, such as uniform and smooth silsesquioxane coatings when using APTES or a “pearl-necklace” morphology using TEOS, enabled either compression recovery and flexibility or low thermal conduction. This investigation of silsesquioxane-bCNF provides a good understanding of the importance of the choice of precursor effect on insulating aerogel properties.
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| 6. |
- Dahlqvist, Martin, 1982-, et al.
(författare)
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Chemical order or disorder - a theoretical stability expose for expanding the compositional space of quaternary metal borides
- 2022
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Ingår i: Materials Advances. - : Royal Society of Chemistry. - 2633-5409. ; 3:6, s. 2908-2917
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Tidskriftsartikel (refereegranskat)abstract
- Inspired by the recent discovery of Ti4MoSiB2, a quaternary phase with out-of-plane chemical order that we denote as o-MAB, we perform an extensive first-principles study to explore the attained chemical order and disorder (solid-solution) upon metal alloying of M(5)AB(2) (T2 phases), with M from Groups 3 to 9 and A = Al, Si, P, Ga, and Ge. We show that the attainable chemistries of T2 can be significantly expanded and predict 35 chemically ordered o-MAB phases and 121 solid solutions of an MM-4 AB(2) stoichiometry. The possibility of realizing o-MAB or solid solution MAB phases combined with multiple elemental combinations previously not observed in these borides suggests an increased property tuning potential. Furthermore, five ternary T2 phases, yet to be synthesized, are also predicted to be stable.
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| 7. |
- de Bruin-Dickason, Caspar, et al.
(författare)
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Valorisation of used lithium-ion batteries into nanostructured catalysts for green hydrogen from boranes
- 2020
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Ingår i: Materials Advances. - : Royal Society of Chemistry (RSC). - 2633-5409. ; 1:7, s. 2279-2285
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Tidskriftsartikel (refereegranskat)abstract
- Cobalt-based Li-ion batteries are produced globally on a massive scale, but most are discarded to landfill at the end of their useful lifetime. In this work, an efficient cobalt catalyst for the hydrolysis of sodium borohydride to dihydrogen was prepared from lithium ion battery waste, providing a second life for valuable minerals. This material is composed of a mixed metal cobalt-aluminium oxide supported on graphene, as elucidated by a combined FTIR, Raman, SEM, scanning transmission electron microscopy with electron energy loss spectroscopy (STEM-EELS) and energy-dispersive X-ray spectroscopy (EDS) study. The obtained metal oxide material, which exhibits an average oxidation state for Co of 2.45, is a languid catalyst at room temperature, but rapid hydrogen production of up to 49 L(H-2) min(-1) g(-1)(Co) was observed in catalytic runs heated to 70 degrees C. This carbon-supported cobalt catalyst is competitive with designed cobalt nanostructured catalysts prepared from pure precursors. This work is illustrative of the opportunities which arise when e-waste is utilised as a mineral resource within the scope of a circular economy.
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| 8. |
- Doppelbauer, David, et al.
(författare)
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P-type cobaltite oxide spinels enable efficient electrocatalytic oxygen evolution reaction
- 2021
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Ingår i: Materials Advances. - : Royal Society of Chemistry. - 2633-5409. ; 2:16, s. 5494-5500
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Tidskriftsartikel (refereegranskat)abstract
- Currently, energy-efficient electrocatalytic oxygen evolution from water involves the use of noble metal oxides. Here, we show that highly p-conducting zinc cobaltite spinel Zn1.2Co1.8O3.5 offers an enhanced electrocatalytic activity for oxygen evolution. We refer to previous studies on sputtered Zn-Co spinels with optimized conductivity for implementation as (p-type) transparent conducting oxides. Based on that, we manufacture off-stoichiometric conducting p-spinel catalytic anodes on tetragonal Ti, Au-Ti and hexagonal Al-doped ZnO carriers and report the evolution of O-2 at Tafel slopes between 40.5 and 48 mV dec(-1) and at overpotentials between 0.35 and 0.43 V (at 10 mA cm(-2)). The anodic stability, i.e., 50 h of continuous O-2 electrolysis in 1 M KOH, suggests that increasing the conductivity is advantageous for electrolysis, particularly for reducing the ohmic losses and ensuring activity across the entire surface. We conclude by pointing out the merits of improving p-doping in Zn-Co spinels by optimized growth on a tetragonal Ti-carrier and their application as dimension-stable 3d-metal anodes.
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| 9. |
- Etman, Ahmed, et al.
(författare)
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Fabrication of Mo1.33CTz (MXene)-cellulose freestanding electrodes for supercapacitor applications
- 2021
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Ingår i: Materials Advances. - : ROYAL SOC CHEMISTRY. - 2633-5409. ; 2:2, s. 743-753
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Tidskriftsartikel (refereegranskat)abstract
- MXenes are two-dimensional (2D) transition metal carbides/nitrides with high potential for energy storage devices owing to their high flexibility, conductivity and specific capacitance. However, MXene films tend to suffer from diffusion limitation of ions within the film, and thus their thickness is commonly reduced to a few micrometers (mass loadings <1 mg cm(-2)). Herein, a straightforward one-step protocol for synthesizing freestanding Mo1.33CTz-cellulose composite electrodes with high MXene loading is reported. By varying the amount of the cellulose content, a high gravimetric capacitance (up to 440 F g(-1) for 45 wt% cellulose content, <similar to>5.9 mu m thick film) and volumetric capacitance (up to 1178 F cm(-3) for 5 wt% cellulose content, similar to 4.8 mu m thick film) is achieved. These capacitance values are superior to those for the pristine MXene film, of a similar MXene loading (1.56 mg cm(-2), similar to 4.2 mu m thick film), delivering values of about 272 F g(-1) and 1032 F cm(-3). Interestingly, the Mo1.33CTz-cellulose composite electrodes display an outstanding capacitance retention (similar to 95%) after 30000 cycles, which is better than those reported for other Mo1.33CTz-based electrodes. Furthermore, the presence of cellulose inside a thick composite electrode (similar to 26 mu m, MXene loading 5.2 mg cm(-2)) offers a novel approach for opening the structure during electrochemical cycling, with resulting high areal capacitance of about 1.4 F cm(-2). A symmetric device of Mo1.33CTz-cellulose electrodes featured a long lifespan of about 35000 cycles and delivered a device capacitance up to 95 F g(-1). The superior performance of the Mo1.33CTz-cellulose electrodes in terms of high gravimetric, volumetric, and areal capacitances, long lifespan, and promising rate capability, paves the way for their use in energy storage devices.
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| 10. |
- Gaio, Servane, et al.
(författare)
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Nanoceria-nanocellulose hybrid materials for delayed release of antibiotic and anti-inflammatory medicines
- 2022
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Ingår i: Materials Advances. - : Royal Society of Chemistry. - 2633-5409. ; 3:19, s. 7228-7234
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Tidskriftsartikel (refereegranskat)abstract
- A novel nanoceria-nanocellulose hybrid material has been developed and evaluated as a potential drug delivery system. Crystalline nanoceria was synthesized in situ in the nanocellulose to obtain a homogenous distribution without extensive particle aggregation. The hybrid materials were loaded with two antibiotic drugs, triclosan and ampicillin, and one anti-inflammatory drug, diclofenac. The bacteriostatic effect on the gram-negative bacteria Escherichia coli was evaluated for the hybrid materials containing triclosan and ampicillin. The nanoceria-nanocellulose hybrid displayed a better retention of ampicillin than triclosan in the disc diffusion test, which is likely due to the presence of the carboxylic acid group in ampicillin that has better affinity for ceria compared to the phenolic group in triclosan. However, drug release studies in solution revealed rapid release of ampicillin and diclofenac, indicative of outer-sphere complexes between ceria and the drugs.
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| 11. |
- Garakani, Sadaf Saeedi, et al.
(författare)
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Template-synthesis of a poly(ionic liquid)-derived Fe1−xS/nitrogen-doped porous carbon membrane and its electrode application in lithium–sulfur batteries
- 2021
-
Ingår i: Materials Advances. - : Royal Society of Chemistry (RSC). - 2633-5409. ; 2:15, s. 5203-5212
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Tidskriftsartikel (refereegranskat)abstract
- This study deals with the facile synthesis of Fe1−xS nanoparticle-containing nitrogen-doped porous carbon membranes (denoted as Fe1−xS/N-PCMs) via vacuum carbonization of hybrid porous poly(ionic liquid) (PIL) membranes, and their successful use as a sulfur host material to mitigate the shuttle effect in lithium–sulfur (Li–S) batteries. The hybrid porous PIL membranes as the sacrificial template were prepared via ionic crosslinking of a cationic PIL with base-neutralized 1,1′-ferrocenedicarboxylic acid, so that the iron source was molecularly incorporated into the template. The carbonization process was investigated in detail at different temperatures, and the chemical and porous structures of the carbon products were comprehensively analyzed. The Fe1−xS/N-PCMs prepared at 900 °C have a multimodal pore size distribution with a satisfactorily high surface area and well-dispersed iron sulfide nanoparticles to physically and chemically confine the LiPSs. The sulfur/Fe1−xS/N-PCM composites were then tested as electrodes in Li–S batteries, showing much improved capacity, rate performance and cycle stability, in comparison to iron sulfide-free, nitrogen-doped porous carbon membranes.
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| 12. |
- García-Fernández, J., et al.
(författare)
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In situ atomic-resolution study of transformations in double polymorph ?/ß-Ga 2 O 3 structures
- 2024
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Ingår i: Materials Advances. - 2633-5409. ; 5:9, s. 3824-3831
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Tidskriftsartikel (refereegranskat)abstract
- Disorder-induced formation of metastable Ga2O3 polymorphs as well as the recovery of the stable state upon annealing attract attention because of the fundamental novelty and rapidly increasing interest in the use of Ga2O3 in practical applications. In this study, double polymorph ?/ß-Ga2O3 structures fabricated by the radiation-induced disorder approach were used as a starting point for systematic in situ annealing electron microscopy experiments. We show that, under the conditions of the TEM in situ annealing, double ?/ß-Ga2O3 polymorph structures remained stable up to 300 °C, when onsets of the ?-to-ß transformation become traceable, leading to a prominent ?- and ß-mixture already at 500 °C. Interestingly, the recrystallization of the ß-Ga2O3 occurs throughout the whole ?-film and the preferential alignments at the newly emerging ?/ß-interfaces are different from that of the initial ?/ß-interface formed as a result of the disorder-induced ordering. The alignments of the two polymorphs are maintained as a function of temperature - with a reduction in the volumetric ratio of ?-domains for increasing annealing temperature. Finally, at 1100 °C, ?-Ga2O3 fully transforms into ß-Ga2O3, without dominating crystallographic relationships or preferred orientations, indicating that energy barriers are not any longer implied limiting factors, because of a sufficiently high thermal energy supply. Thus, these TEM in situ measurements enable a new level of accuracy for assessing polymorphic transformations in Ga2O3
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| 13. |
- Golubevas, Ricardas, et al.
(författare)
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Acrylate–gelatin–carbonated hydroxyapatite (cHAP) composites for dental bone-tissue applications
- 2020
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Ingår i: Materials Advances. - : Royal Society of Chemistry. - 2633-5409. ; 1:6, s. 1675-1684
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Tidskriftsartikel (refereegranskat)abstract
- Various types of scaffolds made of synthetic polymers have been widely studied for bone-tissue applications due to their mechanical strength, biocompatibility and biodegradability, but the hydrophobic nature of synthetic polymers and frequent absence of pores within the scaffolds inhibit cellular attachment, infiltration, and tissue ingrowth. In this study, multi-composite scaffolds composed of dipentaerythritol hexa-acrylate (DPHA), ethylene glycol dimethacrylate (EGDMA), gelatin, and carbonated hydroxyapatite (cHAP) have been made. Percentage ratio of polymer matrix to gelatin was varied 50/50, 75/25, and 95/5 to change the porosity of the resultant scaffolds. The structure, crystallinity, and phase composition of the cHAP were confirmed by FTIR, Raman, XRD and Rietveld analyses, TG/DSC was used to evaluate the distribution of ceramics within the polymer matrix, and FTIR-ATR was used to confirm the molecular structure of composites. SEM/EDS analysis of the scaffolds revealed cavities and irregularities in the surface, and that cHAP was indistinctly exposed on the composite surface, computed tomography (CT) was used to estimate the density and homogeneity of the scaffolds, and the cHAP distribution within the scaffolds was evaluated by conventional radiography. The hydrophilicity of the multi-composite scaffolds was investigated using an aqueous solution of methylene blue dye which showed that the acrylate(75%)–gelatin(25%)–cHAP composite had the highest hydrophilicity. The results suggest that acrylate–gelatin–cHAP scaffolds have a potential for bone-tissue engineering.
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| 14. |
- Hoogendoorn, Billy W., et al.
(författare)
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Cellulose-assisted electrodeposition of zinc for morphological control in battery metal recycling
- 2022
-
Ingår i: Materials Advances. - : Royal Society of Chemistry (RSC). - 2633-5409.
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Tidskriftsartikel (refereegranskat)abstract
- Cellulose nanofibers (CNF) are demonstrated as an effective tool for converting electrodeposits into more easily detachable dendritic deposits useful in recycling zinc ion batteries via electrowinning. The incorporation of CNF at concentrations ranging from 0.01 to 0.5 g/L revealed a progressively extensive formation of a nacre-like dendritic zinc structure that did not form in its absence. Increasing CNF-concentrations from 0.01 to 0.5 g/L resulted in more extensive dendritic structures forming. The explanation to the observed phenomenon is the CNFs ability to strongly interact with the metal ions, i.e., restricting the mobility of the ions towards the electrowinning electrode. At the highest concentration of CNF (0.5 g/L), in combination with the lowest current density (150 A/m2), the electrodeposition was limited to the extent that formed deposits were almost non-existent. The electrodeposition in the presence of CNF was further evaluated at different temperatures: 20, 40 and 60°C. The dendritic formation was increasingly suppressed with increasing temperatures, and at a temperature of 60°C, the electrodeposited morphologies could not be differentiated from the morphologies formed in the absence of the cellulose. The results stemmed from a greater mobility of the metal ions at elevated temperatures, while at the same time suggests an inability of the CNF to strongly associate the metal ions at the elevated temperatures. High-pressure blasted titanium electrodes were used a reference material for accurate comparisons, and electron microscopy (FE-SEM) and X-ray diffraction were used to characterize the zinc morphologies and crystallite sizes, respectively. The article reports the first investigation on how dispersions of highly crystalline cellulose nanofibers can be used as a renewable and functional additive during the recycling of battery metal ions. The metal-ion/cellulose interactions may also allow for structural control in electrodeposition for other applications.
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| 15. |
- Howe, Andrew, et al.
(författare)
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Electrocatalytic water oxidation from a mixed linker MOF based on NU-1000 with an integrated ruthenium-based metallo-linker
- 2022
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Ingår i: Materials Advances. - : Royal Society of Chemistry (RSC). - 2633-5409. ; 3:10, s. 4227-4234
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Tidskriftsartikel (refereegranskat)abstract
- A novel tetratopic metallo-linker, [Ru(tda)(py(PhCOOH)2)2], 1, (tda = 2,2′:6′,2′′-terpyridine-6,6′′-dicarboxylate; py(PhCOOH)2 = (4,4′-(pyridine-3,5-diyl)dibenzoic acid), that is structurally based on one of the most active molecular water oxidation catalysts has been prepared and fully characterized, including single crystal X-ray diffraction. 1 bears geometric similarities to H4TBAPy (H4TBAPy = 4,4′,4′′,4′′′-(pyrene-1,3,6,8-tetrayl)tetrabenzoic acid), i.e. the native linker in NU-1000, which offers the possibility to synthesize NU-1000-Ru mixed linker MOFs solvothermally. Mixed linker MOF formation was demonstrated by powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM), and Ru linker incorporation confirmed by FT-IR, energy-dispersive X-ray (EDX) spectroscopy and inductively coupled plasma optical emission spectroscopy (ICP-OES). It was found that the Ru contents in the final mixed linker MOFs correlate with the amount of Ru linker present during solvothermal synthesis, albeit not in a linear fashion. The cyclic voltammograms (CV) of the mixed linker MOFs are largely dominated by TBAPy-based oxidations with features attributed to 1. Interestingly, Ru linkers near the crystal surface are oxidized directly by interfacial hole transfer form the electrode, while those in the crystal interior can be oxidized indirectly from oxidized TBAPy linkers at more anodic potential. Upon repeated scanning, the CVs show the appearance of new waves that arise from irreversible TBAPy oxidation, as well as from the activation of the Ru-based water oxidation catalyst. Of the materials prepared, the one with the highest Ru content, NU-1000-Ruhigh, was shown to catalyze the electrochemical oxidation of water to dioxygen. The Faradaic efficiency (FE) of the construct is 37%, due to water oxidation being accompanied by oxidative transformations of the TBAPy linkers. Despite the low FE, NU-1000-Ruhigh is still among the best MOF-based water oxidation catalysts, operating by a unique co-linker mediated hole-transport mechanism to supply oxidizing equivalents also to catalysts in the crystal interior.
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| 16. |
- Hu, Yingying, et al.
(författare)
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Visible light excited and temperature-responsive phosphorescent system in a phase-changing matrix
- 2024
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Ingår i: Materials Advances. - : ROYAL SOC CHEMISTRY. - 2633-5409.
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Tidskriftsartikel (refereegranskat)abstract
- Reversibly switching visible light excited phosphorescence emission by external stimuli is highly challenging. Herein, we report a series of tetrakis(arylthio)benzene derivatives with a D-A structure, exhibiting visible-light excited room-temperature phosphorescence. Significantly, the emission from their crystalline powder state responded to mechanical forces, attributed to alterations in molecular stacking changes, resulting in their phosphorescence color changes. Moreover, the monomer and aggregated phosphorescence transition could be reversibly switched by temperature when doping these molecules into a phase-changing matrix saturated fatty acid (FA) because the FA matrix is transformed between solid and fluid states under different temperatures. In addition, multi-color luminescent materials were also obtained by further introducing triphenylamine dye molecules. Finally, these doping systems exhibited excellent application potential in temperature indication and anti-counterfeiting. This successful design strategy provides a new idea for preparing reversible external stimuli-responsive phosphorescent materials. D-A-type tetrakis(arylthio)benzene derivatives exhibited visible-light excited phosphorescence, mechanical-stimuli responsive phosphorescence in solid and temperature-induced phosphorescence changes in the phase-changing doping state.
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| 17. |
- Karlsson, Mattias E., et al.
(författare)
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The effect of ZnO particle lattice termination on the DC conductivity of LDPE nanocomposites
- 2020
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Ingår i: Materials Advances. - : Royal Society of Chemistry (RSC). - 2633-5409. ; 1:6, s. 1653-1664
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Tidskriftsartikel (refereegranskat)abstract
- The effects of particle surface termination by zinc or oxygen were evaluated for composites containing micro-sized ZnO particles with rod shapes (17% oxygen terminations) or ball shapes (67% oxygen terminations), and it was found that the rods gave a conductivity (1.2 x 10(-16) S m(-1)) half that given by the ball-shaped particles (2.4 x 10(-16) S m(-1)). Both composites containing the micro-sized particles showed a conductivity almost two orders of magnitude lower than that of the LDPE reference material (1.2 x 10(-14) S m(-1)). When a 5 nm thick silica coating was applied to the particles, the silica encapsulation eliminated the difference between the particles and resulted in both cases in an increase in conductivity by an order of magnitude to ca. 2 x 10(-15) S m(-1). The conductivity was still lower than that of the pristine polyethylene polymer. It was concluded that neither the particle morphology nor the inter-particle distance (1 mu m for rods and 8 mu m for balls) had any effect on the conductivity of the composites for identically terminated particles, while demonstrating that the conductivity of these materials relies uniquely on the particle surface terminations. In contrast, a markedly reduced conductivity was observed for composites containing the same particles but terminated with aliphatic hydrocarbon tails, the conductivity for both rod-shaped and ball-shaped particles (1 x 10(-16) S m(-1)) being reduced to even lower values than for the pristine particles without surface modification. The same trend was observed with the 25 nm ZnO nanoparticles, showing a record low conductivity of 1 x 10(-17) S m(-1) for 3 wt% nanoparticles with aliphatic hydrocarbon tails. In practical applications, this would permit higher operation voltages than currently employed HVDC cable systems by controlling the resistivity of the composite insulation for various electric fields and temperatures and making it possible to tailor the dielectric design of cable components.
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| 18. |
- Kerr, Hannah E., et al.
(författare)
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Announcing the Materials Advances Paper Prize
- 2023
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Ingår i: Materials Advances. - : Royal Society of Chemistry. - 2633-5409. ; 4:20, s. 4635-4636
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 19. |
- Kore, Bhushan P., et al.
(författare)
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Water-resistant 2D lead(ii) iodide perovskites : correlation between optical properties and phase transitions
- 2020
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Ingår i: Materials Advances. - : Royal Society of Chemistry (RSC). - 2633-5409. ; 1:7, s. 2395-2400
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Tidskriftsartikel (refereegranskat)abstract
- The hybrid perovskite-based solar cells have achieved photovoltaic efficiencies comparable to that of the silicon-based solar cells; however, the light-absorbing perovskite materials are not stable and undergo rapid degradation in the presence of moisture. There are only a few water-stable 2D perovskite materials that have been explored so far. Keeping this in mind, we incorporated 3 different long-chain alkylammonium cations in 2D perovskites using a generic solution synthesis route where the saturated precursor solution was slowly cooled down to room temperature resulting in the single crystals of the 2D perovskites and studied their optical properties and stability against moisture. The prepared 2D perovskites demonstrated robust stability under ambient conditions as well as resistance to water. The main highlight of the present study is 2D perovskites emit bright green light in the 494-520 nm range even in the presence of water. We anticipate that our results on the water stable perovskite will not only motivate the use of these long alkyl chain cation-based 2D perovskite materials in perovskite solar cells for achieving the prolonged device stability but also for the next generation LEDs and display technologies.
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| 20. |
- Kumara, Sarath, 1979, et al.
(författare)
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Invariant electrical conductivity upon thermal ageing of a crosslinked copolymer blend for high voltage insulation
- 2022
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Ingår i: Materials Advances. - : Royal Society of Chemistry (RSC). - 2633-5409. ; 3:11, s. 4718-4723
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Tidskriftsartikel (refereegranskat)abstract
- Click chemistry type reactions between polyethylene-based copolymers are a promising and by-product free alternative to peroxide crosslinking of low-density polyethylene, which is widely used as an insulation material for high-voltage power cables. Here, the impact of thermal ageing on the long-term stability of the thermo-mechanical and dielectric properties of a copolymer blend is evaluated that can be cured through a by-product free reaction between the epoxy and carboxylic acid functional groups attached to the polyethylene backbone. It is observed that ageing at 90 degrees C in air for up to 2500 h does not affect the direct current (DC) electrical conductivity of about 3 x 10(-14) S m(-1), provided that a suitable antioxidant is added that prevents the thermo-oxidative degradation of the polyethylene backbone. Furthermore, the material maintains its thermo-mechanical properties upon ageing such as a high ductility at room temperature and a stiffness of about 1 MPa above the melting temperature of polyethylene. Evidently, the use of click chemistry type reactions is a promising strategy for the design of new high-voltage insulation materials that can be cured without the formation of by-products.
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| 21. |
- Latham, Kenneth G., et al.
(författare)
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Influence of counter ions of ammonium for nitrogen doping and carbon properties in hydrothermal carbonization : characterization and supercapacitor performance
- 2021
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Ingår i: Materials Advances. - : Royal Society of Chemistry. - 2633-5409. ; 2:1, s. 384-397
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Tidskriftsartikel (refereegranskat)abstract
- Ammonium has been successfully utilized to nitrogen dope carbon structures via hydrothermal carbonization, although the influence of different attached counter ions (anions) on the resultant carbon physicochemical properties and electrochemical performance has not been examined before. Four different counter ions (SO42-, PO43-, Cl-, and Fe(SO4)(2)) attached to ammonium were seen to influence the hydrothermal reaction, nitrogen incorporation levels, physicochemical properties, activation ability and supercapacitor performance. For instance, nitrogen K-edge NEXAFS found differences in the levels of pyridinic and pyrrolic groups with PO43- incorporating predominately pyridinic nitrogen groups. PO43- also achieved the highest surface area (2132.6 m(2) g(-1)), however this material was unstable as a supercapacitor, losing almost 50% of its performance over 500 cycles. SO42- resulted in the highest level of nitrogen incorporation (5.53 at%) and hydrothermal yield (45.5%), while Fe(SO4)(2)(2-) resulted in the lowest (2.92 at%). However, Fe(SO4)(2)(2-) produced unique flower like structures not seen in any of the other anions. Cl- produced the highest performing material, achieving 190 F g(-1) at 10 mV s(-1) in 1 M KOH and had moderate nitrogen incorporation (3.42 at%). Overall, this study indicates that the anion has substantial influence on the physicochemical properties of the material, allowing an additional level of tailoring.
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| 22. |
- Layek, R K, et al.
(författare)
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Tailoring of the physical and mechanical properties of biocompatible graphene oxide/gelatin composite nanolaminates via altering the crystal structure and morphology
- 2021
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Ingår i: Materials Advances. - : Royal Society of Chemistry (RSC). - 2633-5409.
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Tidskriftsartikel (refereegranskat)abstract
- Despite substantial progress being made relating to 2D-nanofiller-based composite nanolaminates, the fabrication of composite nanolaminates with enhanced ductility and toughness is still challenging. In this study, layered structure graphene oxide (GO)/gelatin powder (GP) composites nanolaminates with enhanced ductility and toughness have been achieved by a simple vacuum filtration of aqueous dispersion of GO/GP composite solution containing 5 wt% of GO. The composite film containing 5 wt% GO shows outstanding improvement of 200% in the stress at break value, with simultaneous enhancement of 52% of the strain at break value compared to GP film. A significant improvement in toughness from 2.2 MJ m(-3) to 9.5 MJ m(-3) is observed in the composite film containing 5 wt% GO. These significant enhancements of the mechanical properties of the composite film are obtained via the formation of an intercalated nanolaminate structure, H-bonding interactions, and the tailoring of the crystal structure of GP in the composite film, as proved via field-emission scanning electron microscopy, Fourier-transform infrared spectroscopy, and wide-angle X-ray diffraction studies. The growing of fibroblast cells on the composite films signifies that they are not cytotoxic. These GO/GP composites with significant mechanical properties and biocompatibility are very promising for various biomedical applications.
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| 23. |
- Li, Jun, et al.
(författare)
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Tolerance of metal halide perovskites to mechanical treatment enables the fabrication of patterned luminescence nano- and microstructures
- 2022
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Ingår i: Materials Advances. - : Royal Society of Chemistry (RSC). - 2633-5409. ; 27:35
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Tidskriftsartikel (refereegranskat)abstract
- Metal halide perovskites have shown a great performance in a broad range of optoelectronic devices. The variety of preparation methods makes perovskites especially attractive, yet preparation of complex nanostructures based on these materials remains challenging. Here we present a template assisted method allowing to achieve any pre-designed arrangement of methylammonium lead triiodide (MAPbI3) polycrystalline patterns with the spatial resolution defined by the template. We utilized a Si/SiO2 wafer with circular 180 nm deep recesses with diameters ranging from 200 to 1600 nm as a template. A polycrystalline perovskite powder was obtained by scratching off a thin perovskite film and mechanically introduced into the patterned template as a pigment. Scanning electron microscopy revealed that the recesses are filled with tightly packed sub-20 nm crystallites. Considering that the spin-coated film used as a source of MAPbI3 consisted of grains up to 2000 nm in diameter suggests that the initially prepared grains were crashed by rubbing to much smaller crystallites. In spite of this harsh mechanical treatment, the filled recesses showed a strong photoluminescence signal, demonstrating the applicability of this approach for the fabrication of diverse nanophotonic structures.
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| 24. |
- Mathies, Florian, et al.
(författare)
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Gas flow-assisted vacuum drying : Identification of a novel process for attaining high-quality perovskite films
- 2021
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Ingår i: Materials Advances. - : Royal Society of Chemistry (RSC). - 2633-5409. ; 2:16, s. 5365-5370
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Tidskriftsartikel (refereegranskat)abstract
- Controlling the nucleation and crystal growth in solution-processed metal halide perovskite (MHP) thin films is the pivotal point in fabricating homogenous and pinhole-free films. Using scalable coating and printing techniques, vacuum and gas flow-assisted drying processes turn out to be the most promising methods to induce nucleation and crystallization. Yet, the exact interplay and nature of these processes are unclear. In our work, we optically monitor these processes in situ. For the first time, we can show that a controlled venting of the vacuum chamber and the use of a subsequent gas flow are key to achieve homogenous nucleation. Utilizing this gas flow-assisted vacuum drying process, we find that regular, optically dense and pinhole-free MHP layers can be fabricated via inkjet printing, which yield solar cells with a power conversion efficiency of 16%, as compared to 4.5% for vacuum drying.
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| 25. |
- Meng, Qijun, 1990-, et al.
(författare)
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Remarkable synergy of borate and interfacial hole transporter on BiVO4 photoanodes for photoelectrochemical water oxidation
- 2021
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Ingår i: Materials Advances. - : Royal Society of Chemistry (RSC). - 2633-5409. ; 2:13, s. 4323-4332
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Tidskriftsartikel (refereegranskat)abstract
- Bismuth vanadate (BiVO4) is one of the most fascinating building blocks for the design and assembly of highly efficient artificial photosynthesis devices for solar water splitting. Our recent report has shown that borate treated BiVO4 (B-BiVO4) results in an improved water oxidation performance. In this study, further improvement of both the photoelectrochemical (PEC) activity and stability of B-BiVO4 was successfully achieved by introducing NiFeV LDHs as an oxygen evolution catalyst and interfacial hole transporter. Benefiting from the synergistic effect of co-catalyst and borate pretreatment, the as-prepared NiFeV/B-BiVO4 exhibited a high photocurrent density of 4.6 mA cm−2 at 1.23 VRHE and an outstanding onset potential of ∼0.2 VRHE with good long-term stability. More importantly, NiFeV was found to play a pivotal role in the critically efficient suppression of charge combination on the BiVO4 surface and acceleration of charge transfer rather than a mere electrocatalyst for water oxidation.
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