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- Zhang, Ming, et al.
(författare)
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Tethered Small-Molecule Acceptor Refines Hierarchical Morphology in Ternary Polymer Solar Cells: Enhanced Stability and 19% Efficiency
- 2023
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Ingår i: Advanced Materials. - : WILEY-V C H VERLAG GMBH. - 0935-9648 .- 1521-4095.
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Tidskriftsartikel (refereegranskat)abstract
- Polymer solar cells (PSCs) are promising for efficient solar energy conversion, but achieving high efficiency and device longevity within a bulk-heterojunction (BHJ) structure remains a challenge. Traditional small-molecule acceptors (SMAs) in the BHJ blend show thermodynamic instability affecting the morphology. In contrast, tethered SMAs exhibit higher glass transition temperatures, mitigating these concerns. Yet, they might not integrate well with polymer donors, causing pronounced phase separation and overpurification of mixed domains. Herein, a novel ternary device is introduced that uses DY-P2EH, a tethered dimeric SMA with conjugated side-chains as host acceptor, and BTP-ec9, a monomeric SMA as secondary acceptor, which respectively possess hypomiscibility and hypermiscibility with the polymer donor PM6. This unique combination affords a parallel-connected ternary BHJ blend, leading to a hierarchical and stable morphology. The ternary device achieves a remarkable fill factor of 80.61% and an impressive power conversion efficiency of 19.09%. Furthermore, the ternary device exhibits exceptional stability, retaining over 85% of its initial efficiency even after enduring 1100 h of thermal stress at 85 degrees C. These findings highlight the potential advantage of tethered SMAs in the design of ternary devices with a refined hierarchical structure for more efficient and durable solar energy conversion technologies. A ternary-device design is proposed that fully utilizes the individual thermodynamic properties of both dimeric acceptor and monomeric acceptor. The high Tg value of dimeric acceptor significantly impedes the molecular movement of monomeric acceptor, while hypermiscible properties of monomeric acceptor promote percolation of the mixed domain for enhancing charge dynamics.image
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| 3. |
- Ma, Fei, et al.
(författare)
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Association of Leukocyte Telomere Length with Mild Cognitive Impairment and Alzheimer's Disease : Role of Folate and Homocysteine
- 2019
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Ingår i: Dementia and Geriatric Cognitive Disorders. - : S. Karger AG. - 1420-8008 .- 1421-9824. ; 48:1-2, s. 56-67
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Tidskriftsartikel (refereegranskat)abstract
- Background: Leukocyte telomere length (LTL) is associated with the aging process and age-related degenerative diseases. The relation of peripheral blood LTL to mild cognitive impairment (MCI) and Alzheimer's disease (AD) and the role of folate and homocysteine (Hcy) in this relation remain unclear.Objectives: We aimed to investigate the association between LTL and the risks of MCI/AD, and to explore whether folate and Hcy may play a role in this association.Methods: This case-control study included 129 MCI subjects, 131 AD patients and 134 healthy controls. LTL was assessed using real-time polymerase chain reaction assay. Serum folate levels were tested by chemiluminescence enzyme immunoassay, and serum Hcy levels were measured using the enzymatic cycling method. Data were analyzed using multivariate logistic regression and multivariable linear regression with adjustment for potential confounders.Results: The mean LTL was 1.56 +/- 0.25 in controls, 1.44 +/- 0.23 in MCI, and 1.28 +/- 0.28 in AD patients (p< 0.01). In multivariate logistic regression, subjects in the longest LTL tertile had lower OR for MCI (OR 0.246; 95% CI 0.101-0.597) and AD (OR 0.123; 95% CI 0.044-0.345) in comparison to subjects in the shortest tertile. Shorter LTL was dose-dependently related to the ORs of MCI and AD. Further, serum folate concentration was positively associated with LTL (p < 0.01), while serum Hcy level was negatively associated with LTL (p < 0.05). In stratified analyses, LTL-MCI/AD association varied by serum folate and Hcy level. Conclusions: Shorter LTL is associated with the risks of MCI/AD. Folate and Hcy might play an important role in this association.
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| 5. |
- Ma, Fei, et al.
(författare)
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Folic acid supplementation improves cognitive function by reducing the levels of peripheral inflammatory cytokines in elderly Chinese subjects with MCI
- 2016
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- This study aimed to evaluate whether folic acid supplementation would improve cognitive performance by reducing serum inflammatory cytokine concentrations. This RCT was performed in Tianjin, China. Participants with mild cognitive impairment (MCI) were randomly assigned to the folic acid (400 mu g/day) or conventional treatment groups. Neuropsychological tests were administered, and folate, homocysteine, vitamin B-12, IL-6, TNF-alpha, A beta-42, and A beta-40 were measured at baseline and at 6- and 12-month time points. 152 participants (folic acid: 77, conventional: 75) completed the trial. Significant improvements in folate (eta p(2) = 0.703, P = 0.011), homocysteine (eta p(2) = 0.644, P = 0.009), A beta-42 (eta p(2) = 0.687, P = 0.013), peripheral IL-6 (eta p(2) = 0.477, P = 0.025), TNF-alpha (eta p(2) = 0.709, P = 0.009) levels were observed in folic acid group compared with conventional group. Folic acid supplementation improved the Full Scale Intelligence Quotient (P = 0.028; effect size d = 0.153), Information (P = 0.031; d = 0.157) and Digit Span (P = 0.009; d = 0.172) scores at 12 months compared with conventional treatment. Based on these findings, daily oral administration of a 400-mu g folic acid supplement to MCI subjects for 12 months can significantly improve cognitive performance and reduce peripheral inflammatory cytokine levels.
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| 6. |
- Zhang, Rui, et al.
(författare)
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To Reveal the Importance of the Crystallization Sequence on Micro-Morphological Structures of All-Crystalline Polymer Blends by In Situ Investigation
- 2021
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Ingår i: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 13:18, s. 21756-21764
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Tidskriftsartikel (refereegranskat)abstract
- In crystalline/crystalline polymer blend systems, complex competition and coupling of crystallization and morphology usually happen due to the different crystal nucleation and growth processes of polymers, making the morphology and crystallization behavior difficult to control. Herein, we probe the crystallization sequence during the film formation process (crystallize simultaneously, component A crystallizes prior to B or inverse) to illustrate the micro-morphology evolution process in poly(3-hexylthiophene) (P3HT) and poly[[N,N-bis(2-octyldodecyl)-napthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]- alt-5, 5-(2,2-bithiophene)] (N2200) blend using in situ UV-vis absorption spectra and in situ two-dimensional grazing incidence X-ray diffraction (2D GIXRD). When P3HT and N2200 crystallize simultaneously, a large-sized morphology structure is formed. When strengthening the solution aggregation of P3HT by increasing the solvent-polymer interaction, P3HT crystallizes prior to N2200. A P3HT-based micro-morphology structure is obtained. As the molecular weight of N2200 increases to a critical value (72.0 kDa), the crystallization of N2200 dominates the film formation process. A N2200-based micro-morphology is formed guided by N2200 domains. The results confirm that the crystallization sequence is one of the most important factors to determine the micromorphology structure in all-crystalline polymer blends.
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