| 1. |
- Cebrian, Ariane V.S., et al.
(författare)
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Development of Conformable Substrates for OLEDs Using Highly Transparent Bacterial Cellulose Modified with Recycled Polystyrene
- 2022
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Ingår i: Advanced Sustainable Systems. - : Wiley. - 2366-7486. ; 6:2
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Tidskriftsartikel (refereegranskat)abstract
- Bacterial cellulose (BC) is a biocompatible and nontoxic biopolymer that has been successfully used as a substrate for flexible organic light emitting diodes (OLEDs). Although BC membranes exhibit excellent mechanical properties and industrial scalability, they are semitransparent, which limits their performance. To improve the optical properties of BC membranes, methods such as the polymerization of different inorganic–organic hybrid materials and petrochemical derivative monomers have been considered; however, these methods require considerable time and effort. In this work, transparent BC membranes for conformable OLEDs substrates are fabricated by spray coating a solution of recycled petrochemical plastics, found in expanded foam package wastes, and d-limonene, which is a green solvent extracted from orange peels. This fabrication approach is highly scalable and can be considered a sustainable technique to develop high performance transparent substrates for photonic applications based on both recovered petrochemical polymers and naturally occurring biopolymers. In terms of the morphological and structural properties, the resulting transparent membranes exhibit a lower roughness than pristine BC. The resulting BC-PS composite is used as a substrate for OLED fabrication. The conformable OLEDs exhibit a current efficiency of up to 5 cd A−1 (16 000 cd m−2) and power density of ≈2.8 mW cm−2.
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| 2. |
- de Oliveira Barud, Hélida Gomes, et al.
(författare)
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Bacterial Nanocellulose in Dentistry: Perspectives and Challenges
- 2021
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Ingår i: Molecules. - : MDPI AG. - 1420-3049 .- 1420-3049. ; 26:1
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Forskningsöversikt (refereegranskat)abstract
- Bacterial cellulose (BC) is a natural polymer that has fascinating attributes, such as biocompatibility, low cost, and ease of processing, being considered a very interesting biomaterial due to its options for moldability and combination. Thus, BC-based compounds (for example, BC/collagen, BC/gelatin, BC/fibroin, BC/chitosan, etc.) have improved properties and/or functionality, allowing for various biomedical applications, such as artificial blood vessels and microvessels, artificial skin, and wounds dressing among others. Despite the wide applicability in biomedicine and tissue engineering, there is a lack of updated scientific reports on applications related to dentistry, since BC has great potential for this. It has been used mainly in the regeneration of periodontal tissue, surgical dressings, intraoral wounds, and also in the regeneration of pulp tissue. This review describes the properties and advantages of some BC studies focused on dental and oral applications, including the design of implants, scaffolds, and wound-dressing materials, as well as carriers for drug delivery in dentistry. Aligned to the current trends and biotechnology evolutions, BC-based nanocomposites offer a great field to be explored and other novel features can be expected in relation to oral and bone tissue repair in the near future.
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| 3. |
- Fares, Hssen, et al.
(författare)
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Tuning multicolor emission in AgNCs/Tm3+/Mn2+-doped fluorophosphate glasses
- 2020
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Ingår i: Journal of Non-Crystalline Solids. - : Elsevier BV. - 0022-3093. ; 535
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Tidskriftsartikel (refereegranskat)abstract
- Herein we report the synthesis of highly-doped silver nanocluster in fluorophosphate glasses through the melting-quenching method in order to achieve sensitization with Tm3+ and Mn2+ ions. Blue and red emission belonging to Tm3+ (470 to 490 nm) and Mn2+ (550 to 750 nm) ions could be obtained via non-resonant excitation of Tm3+ and Mn2+. Slight decrease of the fluorescence decay times confirmed an energy transfer as a possible mechanism to explain the Tm3+ and Mn2+ emission. The composition of 5 mol% of AgNO3, 0.4 mol% of Tm2O3 and 0.2 mol% of MnF2 in our sample leads to distance between donor (silver nanoclusters) and acceptor (Tm3+-Mn2+) as short as 11 Å, which suggests that the main mechanism for blue and red emission from Tm3+ and Mn2+ is Förster Resonance Energy Transfer (FRET). The results presented here show that the studied material has potential application for multicolor generation as luminophore in white light emitting diodes (W-LED).
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| 4. |
- Lara-Cerón, Jesús A., et al.
(författare)
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Ultrasound-assisted synthesis of organotin compounds and their application as luminescent dye in silk fibroin scaffolds
- 2020
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Ingår i: Inorganica Chimica Acta. - : Elsevier BV. - 0020-1693. ; 505
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we report the green synthesis of four luminescent organotin compounds 1–4 derived from amino acid Schiff bases (1: Naph-Trp-SnPh2, 2: Naph-Tyr-SnBu2, 3: Naph-Tyr-SnPh2, 4: Naph-Phe-SnPh2), obtained by ultrasound-assisted synthesis in short time (~20 min) and good yields (>95%). The molecular structure proposed in solution (1H and 119Sn NMR) was confirmed by X-ray diffraction study for compound 1 where the tin atom resides in trigonal bipyramid geometry. Luminescent silk fibroin scaffolds (SF 1–4) were elaborated with organotin compounds by freeze-drying technique. Photophysical properties of organotin compounds and scaffolds were obtained in solid state, observing bathochromic behaviors in tyrosine derived compounds, suggesting that the tyrosine produce supramolecular interactions across the –OH group that change the fluorescent properties. Scaffolds 1–4 were characterized by FTIR, XDR, TG/DTG, and SEM analysis. In addition, cytotoxic analysis of SF 1 presents high cellular viability, which could be applied as a scaffold in tissue engineering.
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| 5. |
- Mendoza-Galvan, Arturo, et al.
(författare)
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Mueller matrix spectroscopic ellipsometry study of chiral nanocrystalline cellulose films
- 2018
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Ingår i: Journal of Optics. - : IOP PUBLISHING LTD. - 2040-8978 .- 2040-8986. ; 20:2
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Tidskriftsartikel (refereegranskat)abstract
- Chiral nanocrystalline cellulose (NCC) free-standing films were prepared through slow evaporation of aqueous suspensions of cellulose nanocrystals in a nematic chiral liquid crystal phase. Mueller matrix (MM) spectroscopic ellipsometry is used to study the polarization and depolarization properties of the chiral films. In the reflection mode, the MM is similar to the matrices reported for the cuticle of some beetles reflecting near circular left-handed polarized light in the visible range. The polarization properties of light transmitted at normal incidence for different polarization states of incident light are discussed. By using a differential decomposition of the MM, the structural circular birefringence and dichroism of a NCC chiral film are evaluated.
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| 6. |
- Sábio, Rafael M., et al.
(författare)
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Near-Infrared Luminescence from Visible-Light-Sensitized Ruthenium(II)-Neodymium(III) Heterobimetallic Bridged Complexes Containing Alkoxy(silyl) Functional Groups
- 2020
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Ingår i: Journal of the Brazilian Chemical Society. - : Sociedade Brasileira de Quimica (SBQ). - 0103-5053 .- 1678-4790. ; 31:4, s. 694-702
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Tidskriftsartikel (refereegranskat)abstract
- New infrared emitting d-f (ruthenium(II)–neodymium(III)) heterobimetallic complexes with alkoxy(silyl) functional groups have been prepared. Visible excitation evidenced energy transfer processes from the ruthenium(II) donor to neodymium(III) acceptors leading to infrared emission. Energy transfer rates (kEnT) and efficiency of energy transfer (ηEnT) are, respectively, 0.61 × 107 s-1 and 44% for RuL1–NdL3 complex. Larger values of kEnT (3.04 × 107 s-1) and ηEnT (84%) were detected for RuL2–NdL4 complex. RuL1–NdL3 and RuL2–NdL4 complexes were fully characterized by elementary analysis (EA), mass spectrometry (MS), Fourier transform infrared spectroscopy (FTIR) and Fourier transform Raman spectroscopy (FT-Raman). Total correlation spectroscopy (TOCSY1D), 1H{13C} heteronuclear single quantum correlation (HSQC) and 1H{13C} heteronuclear multiple bond correlation (HMBC) nuclear magnetic resonance (NMR) analyses were also carried out to characterize NdL3 and RuL1–NdL3 complexes. The presence of trialkoxysilyl-substituted ligands would allow further grafting onto any silica or silicated surface aiming at applications as new luminescent near infrared (NIR)-emitting biosensors or biomarkers.
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