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| 2. |
- Migliaccio, Ludovico, et al.
(author)
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Aqueous photo(electro)catalysis with eumelanin thin films
- 2018
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In: Materials Horizons. - : ROYAL SOC CHEMISTRY. - 2051-6347 .- 2051-6355. ; 5:5, s. 984-990
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Journal article (peer-reviewed)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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| 3. |
- Norrbo, Isabella, et al.
(author)
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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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In: Materials Horizons. - : Royal Society of Chemistry (RSC). - 2051-6347 .- 2051-6355. ; 5:3, s. 569-576
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Journal article (peer-reviewed)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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| 4. |
- Szlachetko, Jakub, et al.
(author)
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Hidden gapless states during thermal transformations of preorganized zinc alkoxides to zinc oxide nanocrystals
- 2018
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In: Materials Horizons. - : Royal Society of Chemistry (RSC). - 2051-6347 .- 2051-6355. ; 5:5, s. 905-911
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Journal article (peer-reviewed)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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| 5. |
- Tallia, F, et al.
(author)
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Bouncing and 3D printable hybrids with self-healing properties
- 2018
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In: MATERIALS HORIZONS. - : Royal Society of Chemistry (RSC). - 2051-6347 .- 2051-6355. ; 5:5, s. 849-860
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Journal article (other academic/artistic)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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| 6. |
- Xu, Weidong, 1988-, et al.
(author)
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The progress and prospects of non-fullerene acceptors in ternary blend organic solar cells
- 2018
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In: Materials Horizons. - : ROYAL SOC CHEMISTRY. - 2051-6347 .- 2051-6355. ; 5:2, s. 206-221
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Research review (peer-reviewed)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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