| 1. |
- Leebens-Mack, James H., et al.
(författare)
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One thousand plant transcriptomes and the phylogenomics of green plants
- 2019
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Ingår i: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 574:7780, s. 679-
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Tidskriftsartikel (refereegranskat)abstract
- Green plants (Viridiplantae) include around 450,000-500,000 species(1,2) of great diversity and have important roles in terrestrial and aquatic ecosystems. Here, as part of the One Thousand Plant Transcriptomes Initiative, we sequenced the vegetative transcriptomes of 1,124 species that span the diversity of plants in a broad sense (Archaeplastida), including green plants (Viridiplantae), glaucophytes (Glaucophyta) and red algae (Rhodophyta). Our analysis provides a robust phylogenomic framework for examining the evolution of green plants. Most inferred species relationships are well supported across multiple species tree and supermatrix analyses, but discordance among plastid and nuclear gene trees at a few important nodes highlights the complexity of plant genome evolution, including polyploidy, periods of rapid speciation, and extinction. Incomplete sorting of ancestral variation, polyploidization and massive expansions of gene families punctuate the evolutionary history of green plants. Notably, we find that large expansions of gene families preceded the origins of green plants, land plants and vascular plants, whereas whole-genome duplications are inferred to have occurred repeatedly throughout the evolution of flowering plants and ferns. The increasing availability of high-quality plant genome sequences and advances in functional genomics are enabling research on genome evolution across the green tree of life.
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| 2. |
- Lin, Yuze, et al.
(författare)
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Mapping Polymer Donors toward High-Efficiency Fullerene Free Organic Solar Cells
- 2017
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Ingår i: Advanced Materials. - : WILEY-V C H VERLAG GMBH. - 0935-9648 .- 1521-4095. ; 29:3
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Tidskriftsartikel (refereegranskat)abstract
- Five polymer donors with distinct chemical structures and different electronic properties are surveyed in a planar and narrow-bandgap fused-ring electron acceptor (IDIC)-based organic solar cells, which exhibit power conversion efficiencies of up to 11%.
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| 3. |
- Zhou, Ruimin, et al.
(författare)
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All-small-molecule organic solar cells with over 14% efficiency by optimizing hierarchical morphologies
- 2019
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Ingår i: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- The high efficiency all-small-molecule organic solar cells (OSCs) normally require optimized morphology in their bulk heterojunction active layers. Herein, a small-molecule donor is designed and synthesized, and single-crystal structural analyses reveal its explicit molecular planarity and compact intermolecular packing. A promising narrow bandgap small-molecule with absorption edge of more than 930 nm along with our home-designed small molecule is selected as electron acceptors. To the best of our knowledge, the binary all-small-molecule OSCs achieve the highest efficiency of 14.34% by optimizing their hierarchical morphologies, in which the donor or acceptor rich domains with size up to ca. 70 nm, and the donor crystals of tens of nanometers, together with the donor-acceptor blending, are proved coexisting in the hierarchical large domain. All-small-molecule photovoltaic system shows its promising for high performance OSCs, and our study is likely to lead to insights in relations between bulk heterojunction structure and photovoltaic performance.
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| 4. |
- Cui, Yong, et al.
(författare)
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Over 16% efficiency organic photovoltaic cells enabled by a chlorinated acceptor with increased open-circuit voltages
- 2019
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Ingår i: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Broadening the optical absorption of organic photovoltaic (OPV) materials by enhancing the intramolecular push-pull effect is a general and effective method to improve the power conversion efficiencies of OPV cells. However, in terms of the electron acceptors, the most common molecular design strategy of halogenation usually results in down-shifted molecular energy levels, thereby leading to decreased open-circuit voltages in the devices. Herein, we report a chlorinated non-fullerene acceptor, which exhibits an extended optical absorption and meanwhile displays a higher voltage than its fluorinated counterpart in the devices. This unexpected phenomenon can be ascribed to the reduced non-radiative energy loss (0.206 eV). Due to the simultaneously improved short-circuit current density and open-circuit voltage, a high efficiency of 16.5% is achieved. This study demonstrates that finely tuning the OPV materials to reduce the bandgap-voltage offset has great potential for boosting the efficiency.
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| 5. |
- Tang, Ailing, et al.
(författare)
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Simultaneously Achieved High Open-Circuit Voltage and Efficient Charge Generation by Fine-Tuning Charge-Transfer Driving Force in Nonfullerene Polymer Solar Cells
- 2018
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Ingår i: Advanced Functional Materials. - : WILEY-V C H VERLAG GMBH. - 1616-301X .- 1616-3028. ; 28:6
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Tidskriftsartikel (refereegranskat)abstract
- To maximize the short-circuit current density (J(SC)) and the open circuit voltage (V-OC) simultaneously is a highly important but challenging issue in organic solar cells (OSCs). In this study, a benzotriazole-based p-type polymer (J61) and three benzotriazole-based nonfullerene small molecule acceptors (BTA1-3) are chosen to investigate the energetic driving force for the efficient charge transfer. The lowest unoccupied molecular orbital (LUMO) energy levels of small molecule acceptors can be fine-tuned by modifying the end-capping units, leading to high V-OC (1.15-1.30 V) of OSCs. Particularly, the LUMO energy level of BTA3 satisfies the criteria for efficient charge generation, which results in a high V-OC of 1.15 V, nearly 65% external quantum efficiency, and a high power conversion efficiency (PCE) of 8.25%. This is one of the highest V-OC in the high-performance OSCs reported to date. The results imply that it is promising to achieve both high J(SC) and V-OC to realize high PCE with the carefully designed nonfullerene acceptors.
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| 6. |
- Zhang, Yun, et al.
(författare)
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Fluorination vs. chlorination: a case study on high performance organic photovoltaic materials
- 2018
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Ingår i: Science in China Series B. - : SCIENCE PRESS. - 1674-7291 .- 1869-1870. ; 61:10, s. 1328-1337
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Tidskriftsartikel (refereegranskat)abstract
- Halogenation is a very efficient chemical modification method to tune the molecular energy levels, absorption spectra and molecular packing of organic semiconductors. Recently, in the field of organic solar cells (OSCs), both fluorine- and chlorinesubstituted photovoltaic materials, including donors and acceptors, demonstrated their great potentials in achieving high power conversion efficiencies (PCEs), raising a question that how to make a decision between fluorination and chlorination when designing materials. Herein, we systemically studied the impact of fluorination and chlorination on the properties of resulting donors (PBDB-T-2F and PBDB-T-2Cl) and acceptors (IT-4F and IT-4Cl). The results suggest that all the OSCs based on different donor and acceptor combinations can deliver good PCEs around 13%-14%. Chlorination is more effective than fluorination in downshifting the molecular energy levels and broadening the absorption spectra. The influence of chlorination and fluorination on the crystallinity of the resulting materials is dependent on their introduction positions. As chlorination has the advantage of easy synthesis, it is more attractive in designing low-cost photovoltaic materials and therefore may have more potential in largescale applications.
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