| 1. |
- Betker, Marie, et al.
(författare)
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Sprayed Hybrid Cellulose Nanofibril-Silver Nanowire Transparent Electrodes for Organic Electronic Applications
- 2023
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Ingår i: ACS Applied Nano Materials. - : American Chemical Society (ACS). - 2574-0970. ; 6:14, s. 13677-13688
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Tidskriftsartikel (refereegranskat)abstract
- In times of climate change and resource scarcity, researchers are aiming to find sustainable alternatives to synthetic polymers for the fabrication of biodegradable, eco-friendly, and, at the same time, high-performance materials. Nanocomposites have the ability to combine several favorable properties of different materials in a single device. Here, we evaluate the suitability of two kinds of inks containing silver nanowires for the fast, facile, and industrial-relevant fabrication of two different types of cellulose-based silver nanowire electrodes via layer-by-layer spray deposition only. The Type I electrode has a layered structure, which is composed of a network of silver nanowires sprayed on top of a cellulose nanofibrils layer, while the Type II electrode consists of a homogeneous mixture of silver nanowires and cellulose nanofibrils. A correlation between the surface structure, conductivity, and transparency of both types of electrodes is established. We use the Haacke figure of merit for transparent electrode materials to demonstrate the favorable influence of cellulose nanofibrils in the spray ink by identifying Type II as the electrode with the lowest sheet resistance (minimum 5 ± 0.04 Ω/sq), while at the same time having a lower surface roughness and shorter fabrication time than Type I. Finally, we prove the mechanical stability of the Type II electrode by bending tests and its long-time stability under ambient conditions. The results demonstrate that the mixed spray ink of silver nanowires and cellulose nanofibrils is perfectly suitable for the fast fabrication of highly conductive organic nanoelectronics on an industrial scale.
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| 2. |
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| 3. |
- Brett, Calvin, et al.
(författare)
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Water-Induced Structural Rearrangements on the Nanoscale in Ultrathin Nanocellulose Films
- 2019
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Ingår i: Macromolecules. - : American Chemical Society (ACS). - 0024-9297 .- 1520-5835. ; 52:12, s. 4721-4728
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Tidskriftsartikel (refereegranskat)abstract
- Many nanoscale biopolymer building blocks with defect-free molecular structure and exceptional mechanical properties have the potential to surpass the performance of existing fossil-based materials with respect to barrier properties, load-bearing substrates for advanced functionalities, as well as light-weight construction. Comprehension and control of performance variations of macroscopic biopolymer materials caused by humidity-driven structural changes at the nanoscale are imperative and challenging. A long-lasting challenge is the interaction with water molecules causing reversible changes in the intrinsic molecular structures that adversely affects the macroscale performance. Using in situ advanced X-ray and neutron scattering techniques, we reveal the structural rearrangements at the nanoscale in ultrathin nanocellulose films with humidity variations. These reversible rearrangements are then correlated with wettability that can be tuned. The results and methodology have general implications not only on the performance of cellulose-based materials but also for hierarchical materials fabricated with other organic and inorganic moisture-sensitive building blocks.
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| 4. |
- Harder, Constantin, et al.
(författare)
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Optical Properties of Slot‐Die Coated Hybrid Colloid/Cellulose‐Nanofibril Thin Films
- 2023
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Ingår i: Advanced Optical Materials. - : Wiley. - 2162-7568 .- 2195-1071. ; 11:13
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Tidskriftsartikel (refereegranskat)abstract
- Correlating nanostructure and optical properties of thin hybrid films is the crucial ingredient for designing sustainable applications ranging from structural colors in anticounterfeiting to sensors. Here, the tailoring of the refractive index of hybrid cellulose nanofibril/water-dispersed colloidal ink thin films is presented. The authors apply scalable, layer-by-layer slot-die coating for preparing the cellulose nanofibril and hybrid thin films. Making use of the mobility of the polymer chains in the colloids upon annealing, the influence of the different colloid sizes and their glass transition temperature on the refractive index of the hybrid material is shown. The complex refractive indices of the thin films are characterized by spectroscopic ellipsometry and correlated to the different nanostructures of the thin films. The authors find that post-deposition annealing changes the colloidal nanostructure from particulate to agglomerates. Depending on the size of the colloids, imbibition of the colloids into the cellulose nanofibril template is observed. This scalable approach offers new avenues in structural color functional biomaterial hybrid layers.
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| 5. |
- Jiang, Xinyu, et al.
(författare)
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Film Formation Kinetics of Polymer Donor and Nonfullerene Acceptor Active Layers During Printing Out of 1,2,4-Trimethylbenzene in Ambient Conditions
- 2023
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Ingår i: Solar RRL. - : Wiley. - 2367-198X. ; 7:6
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Tidskriftsartikel (refereegranskat)abstract
- Slot-die coating is a promising upscaling fabrication method to promote commercialization in the field of organic solar cells. Herein, the nonfullerene active layer blend of a conjugated polymer PffBT4T-2OD and a small molecule acceptor EH-IDTBR, which is printed out of the nonhalogenated solvent 1,2,4-trimethylbenzene, is studied. The film formation kinetics of the active layer PffBT4T-2OD:EH-IDTBR is probed in terms of the temporal evolutions in morphology as well as molecular conformation and aggregation as revealed by in situ grazing-incidence small angle X-ray scattering and UV–vis spectroscopy during the film printing process. A five-regime mesoscale domain growth process is observed in the active layer from the liquid state to the final dry state. The solvent evaporation-induced domain growth is accompanied with molecular stacking in a distinct J-type aggregation of the acceptor and a slight H-type aggregation of the donor molecules. The printed active layers exhibit an edge-on dominated PffBT4T-2OD and a face-on dominated EH-IDTBR crystallite structure. Compared to the neat PffBT4T-2OD and EH-IDTBR films, in the active layer, the crystallite structure deviates slightly in lattice spacing.
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