| 1. |
- Chen, Haiyang, et al.
(författare)
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A guest-assisted molecular-organization approach for >17% efficiency organic solar cells using environmentally friendly solvents
- 2021
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Ingår i: Nature Energy. - : NATURE PORTFOLIO. - 2058-7546. ; 6:11, s. 1045-1053
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Tidskriftsartikel (refereegranskat)abstract
- The power conversion efficiencies (PCEs) of laboratory-sized organic solar cells (OSCs), usually processed from low-boiling-point and toxic solvents, have reached high values of over 18%. However, there is usually a notable drop of the PCEs when green solvents are used, limiting practical development of OSCs. Herein, we obtain certificated PCEs over 17% in OSCs processed from a green solvent paraxylene (PX) by a guest-assisted assembly strategy, where a third component (guest) is employed to manipulate the molecular interaction of the binary blend. In addition, the high-boiling-point green solvent PX also enables us to deposit a uniform large-area module (36 cm(2)) with a high efficiency of over 14%. The strong molecular interaction between the host and guest molecules also enhances the operational stability of the devices. Our guest-assisted assembly strategy provides a unique approach to develop large-area and high-efficiency OSCs processed from green solvents, paving the way for industrial development of OSCs. Organic solar cells processed from green solvents are easier to implement in manufacturing yet their efficiency is low. Chen et al. devise a guest molecule to improve the molecular packing, enabling devices with over 17% efficiency.
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| 2. |
- Huang, Yuting, et al.
(författare)
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Host-Guest Strategy Enabling Nonhalogenated Solvent Processing for High-Performance All-Polymer Hosted Solar Cells
- 2023
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Ingår i: Chinese journal of chemistry. - : WILEY-V C H VERLAG GMBH. - 1001-604X .- 1614-7065. ; 41:9, s. 1066-1074
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Tidskriftsartikel (refereegranskat)abstract
- The power conversion efficiencies (PCEs) of all-polymer solar cells (all-PSCs), usually processed from low-boiling-point and toxic solvents, have reached high values of 18%. However, poor miscibility and uncontrollable crystallinity in polymer blends lead to a notable drop in the PCEs when using green solvents, limiting the practical development of all-PSCs. Herein, a third component (guest) BTO was employed to optimize the miscibility and enhance the crystallinity of PM6/PY2Se-F host film processed from green solvent toluene (TL), which can effectively suppress the excessive aggregation of PY2Se-F and facilitate a nano-scale interpenetrating network morphology for exciton dissociation and charge transport. As a result, TL-processed all-polymer hosted solar cells (all-PHSCs) exhibited an impressive PCE of 17.01%. Moreover, the strong molecular interaction between the host and guest molecules also enhances the thermal stability of the devices. Our host-guest strategy provides a unique approach to developing high-efficiency and stable all-PHSCs processed from green solvents, paving the way for the industrial development of all-PHSCs.
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| 3. |
- Chen, Haiyang, et al.
(författare)
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Heterogeneous Nucleating Agent for High-Boiling-Point Nonhalogenated Solvent-Processed Organic Solar Cells and Modules
- 2024
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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
- High-boiling-point nonhalogenated solvents are superior solvents to produce large-area organic solar cells (OSCs) in industry because of their wide processing window and low toxicity; while, these solvents with slow evaporation kinetics will lead excessive aggregation of state-of-the-art small molecule acceptors (e.g. L8-BO), delivering serious efficiency losses. Here, a heterogeneous nucleating agent strategy is developed by grafting oligo (ethylene glycol) side-chains on L8-BO (BTO-BO). The formation energy of the obtained BTO-BO; while, changing from liquid in a solvent to a crystalline phase, is lower than that of L8-BO irrespective of the solvent type. When BTO-BO is added as the third component into the active layer (e.g. PM6:L8-BO), it easily assembles to form numerous seed crystals, which serve as nucleation sites to trigger heterogeneous nucleation and increase nucleation density of L8-BO through strong hydrogen bonding interactions even in high-boiling-point nonhalogenated solvents. Therefore, it can effectively suppress excessive aggregation during growth, achieving ideal phase-separation active layer with small domain sizes and high crystallinity. The resultant toluene-processed OSCs exhibit a record power conversion efficiency (PCE) of 19.42% (certificated 19.12%) with excellent operational stability. The strategy also has superior advantages in large-scale devices, showing a 15.03-cm2 module with a record PCE of 16.35% (certificated 15.97%). The heterogeneous nucleating agent (BTO-BO) is developed to suppress the excessive aggregation of L8-BO in high-boiling-point nonhalogenated solvents processing, achieving the active layer with high crystallinity and nano-scaled phase separation morphology. The resultant OSCs achieve record power conversion efficiencies of 19.42% (0.062-cm2) and 16.35% (15. 03-cm2) with excellent operational stabilities. image
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| 4. |
- Yang, Heyi, et al.
(författare)
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Composition-Conditioning Agent for Doped Spiro-OMeTAD to Realize Highly Efficient and Stable Perovskite Solar Cells
- 2022
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Ingår i: Advanced Energy Materials. - : WILEY-V C H VERLAG GMBH. - 1614-6832 .- 1614-6840. ; 12:44
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Tidskriftsartikel (refereegranskat)abstract
- The doped Spiro-OMeTAD hole transport layer (HTL) formed using the lithium bis(trifluoromethane) sulfonimide salt and 4-tert-butylpyridine with phenethylammonium iodide surface treatment on a perovskite film has continuously dominated the record power conversion efficiencies (PCEs) of perovskite solar cells (pero-SCs). However, unstable HTL compositions and iodide salts can cause severe device degradation. In this study, an HTL composition-conditioning agent (CCA), Spiro-BD-2OEG, is designed, which contains a Spiro-OMeTAD-like backbone, functional pyridine units, and oligo (ethylene glycol) chains. This finely designed CCA presents good miscibility with Spiro-OMeTAD and its dopants and acts as a conditioning agent through weak bond interactions. As a result, the CCA-regulated HTL shows a pinhole-free and smooth morphology with enhanced Spiro-OMeTAD ordering and improves dopant stability. In addition, the gradient-distributed CCA in the HTL can narrow the energy level offset with the valence band of the perovskite. The resultant pero-SCs exhibit an excellent PCE of 24.19% without any interface treatment and weak size dependence. A remarkable PCE of 22.63% is obtained even for a 1.004-cm(2) device. Importantly, the strategy shows good universality and significantly promotes the long-term stability of the pero-SCs based on the classical doped Spiro-OMeTAD.
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| 5. |
- Zhang, Ben, et al.
(författare)
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Rapid solidification for green-solvent-processed large-area organic solar modules with >16% efficiency
- 2024
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Ingår i: Energy & Environmental Science. - : ROYAL SOC CHEMISTRY. - 1754-5692 .- 1754-5706.
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Tidskriftsartikel (refereegranskat)abstract
- Enabling green-solvent-processed large-area organic solar cells (OSCs) is of great significance to their industrialization. However, precisely controlling the temperature-dependent fluid mechanics and evaporation behavior of green solvents with high-boiling points is challenging. Controlling these parameters is essential to prevent the non-uniform distribution of active layer components and severe molecule aggregation, which collectively degrade the power conversion efficiency (PCE) of large-scale devices. In this study, we revealed that the temperature gradient distribution across a wet film is the root of the notorious Marangoni effect, which leads to the formation of a severely non-uniform active layer on a large scale. Thus, a rapid solidification strategy was proposed to accelerate the evaporation of toluene, a green solvent, at room temperature. This strategy simultaneously inhibits the Marangoni effect and suppresses molecular aggregation in the wet film, allowing the formation of a nano-scale phase separation active layer with uniform morphology. The resultant toluene-processed 15.64-cm2 large-area OSC module achieves an outstanding PCE of 16.03% (certified: 15.69%), which represents the highest reported PCE of green-solvent-processed OSC modules. Notably, this strategy also exhibits a weak scale dependence on the PCE, and we successfully achieved a state-of-the-art PCE of 14.45% for a 72.00-cm2 OSC module. A rapid solidification strategy was developed for simultaneously avoiding the Marangoni effect and suppressing molecular aggregation. The resultant 15.64 cm2 large-area OSC module exhibited a record power conversion efficiency of 16.03%.
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| 6. |
- Chen, Kuan, et al.
(författare)
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Characterization and protein engineering of glycosyltransferases for the biosynthesis of diverse hepatoprotective cycloartane-type saponins in Astragalus membranaceus
- 2023
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Ingår i: Plant Biotechnology Journal. - : John Wiley & Sons. - 1467-7644 .- 1467-7652. ; 21:4, s. 698-710
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Tidskriftsartikel (refereegranskat)abstract
- Although plant secondary metabolites are important source of new drugs, obtaining these compounds is challenging due to their high structural diversity and low abundance. The roots of Astragalus membranaceus are a popular herbal medicine worldwide. It contains a series of cycloartane-type saponins (astragalosides) as hepatoprotective and antivirus components. However, astragalosides exhibit complex sugar substitution patterns which hindered their purification and bioactivity investigation. In this work, glycosyltransferases (GT) from A. membranaceus were studied to synthesize structurally diverse astragalosides. Three new GTs, AmGT1/5 and AmGT9, were characterized as 3-O-glycosyltransferase and 25-O-glycosyltransferase of cycloastragenol respectively. AmGT1(G146V/I) variants were obtained as specific 3-O-xylosyltransferases by sequence alignment, molecular modelling and site-directed mutagenesis. A combinatorial synthesis system was established using AmGT1/5/9, AmGT1(G146V/S) and the reported AmGT8 and AmGT8(A394F). The system allowed the synthesis of 13 astragalosides in Astragalus root with conversion rates from 22.6% to 98.7%, covering most of the sugar-substitution patterns for astragalosides. In addition, AmGT1 exhibited remarkable sugar donor promiscuity to use 10 different donors, and was used to synthesize three novel astragalosides and ginsenosides. Glycosylation remarkably improved the hepatoprotective and SARS-CoV-2 inhibition activities for triterpenoids. This is one of the first attempts to produce a series of herbal constituents via combinatorial synthesis. The results provided new biocatalytic tools for saponin biosynthesis.
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