| 1. |
- Fan, Qunping, 1989, et al.
(författare)
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A Non-Conjugated Polymer Acceptor for Efficient and Thermally Stable All-Polymer Solar Cells
- 2020
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Ingår i: Angewandte Chemie - International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 59:45, s. 19835-19840
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Tidskriftsartikel (refereegranskat)abstract
- A non-conjugated polymer acceptor PF1-TS4 was firstly synthesized by embedding a thioalkyl segment in the mainchain, which shows excellent photophysical properties on par with a fully conjugated polymer, with a low optical band gap of 1.58 eV and a high absorption coefficient >105 cm−1, a high LUMO level of −3.89 eV, and suitable crystallinity. Matched with the polymer donor PM6, the PF1-TS4-based all-PSC achieved a power conversion efficiency (PCE) of 8.63 %, which is ≈45 % higher than that of a device based on the small molecule acceptor counterpart IDIC16. Moreover, the PF1-TS4-based all-PSC has good thermal stability with ≈70 % of its initial PCE retained after being stored at 85 °C for 180 h, while the IDIC16-based device only retained ≈50 % of its initial PCE when stored at 85 °C for only 18 h. Our work provides a new strategy to develop efficient polymer acceptor materials by linkage of conjugated units with non-conjugated thioalkyl segments.
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| 2. |
- Peng, X., et al.
(författare)
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Photodissociation of particulate nitrate as a source of daytime tropospheric Cl2
- 2022
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Chlorine atoms (Cl) are highly reactive and can strongly influence the abundances of climate and air quality-relevant trace gases. Despite extensive research on molecular chlorine (Cl2), a Cl precursor, in the polar atmosphere, its sources in other regions are still poorly understood. Here we report the daytime Cl2 concentrations of up to 1 ppbv observed in a coastal area of Hong Kong, revealing a large daytime source of Cl2 (2.7 pptv s−1 at noon). Field and laboratory experiments indicate that photodissociation of particulate nitrate by sunlight under acidic conditions (pH < 3.0) can activate chloride and account for the observed daytime Cl2 production. The high Cl2 concentrations significantly increased atmospheric oxidation. Given the ubiquitous existence of chloride, nitrate, and acidic aerosols, we propose that nitrate photolysis is a significant daytime chlorine source globally. This so far unaccounted for source of chlorine can have substantial impacts on atmospheric chemistry. © 2022, The Author(s).
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| 3. |
- Fan, Qunping, 1989, et al.
(författare)
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Over 14% efficiency all-polymer solar cells enabled by a low bandgap polymer acceptor with low energy loss and efficient charge separation
- 2020
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry. - 1754-5692 .- 1754-5706. ; 13:12, s. 5017-5027
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Tidskriftsartikel (refereegranskat)abstract
- Obtaining both high open-circuit voltage (V-oc) and short-circuit current density (J(sc)) has been a major challenge for efficient all-polymer solar cells (all-PSCs). Herein, we developed a polymer acceptor PF5-Y5 with excellent optical absorption capability (onset extending to similar to 880 nm and maximum absorption coefficient exceeding 105 cm(-1) in a film), high electron mobility (3.18 x 10(3) cm(2) V-1 s(-1)) and high LUMO level (-3.84 eV) to address such a challenge. As a result, the PBDB-T:PF5-Y5-based all-PSCs achieved a high power conversion efficiency of up to 14.45% with both a high Voc (0.946 V) and a high Jsc (20.65 mA cm(-2)), due to the high and broad absorption coverage, small energy loss (0.57 eV) and efficient charge separation and transport in the device, which are among the best values in the all-PSC field. In addition, the all-PSC shows a similar to 15% improvement in PCE compared to its counterpart small molecule acceptor (Y5)-based device. Our results suggest that PF5-Y5 is a very promising polymer acceptor candidate for applications in efficient all-PSCs.
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| 4. |
- Gao, Fuyuan, et al.
(författare)
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Rapid retreat of the East Asian summer monsoon on the western Chinese loess Plateau during the middle to late Holocene and its environmental and societal implications
- 2023
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Ingår i: Catena (Cremlingen. Print). - 0341-8162 .- 1872-6887. ; 231
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Tidskriftsartikel (refereegranskat)abstract
- Spatiotemporal changes in the Holocene climate of the arid region of China were principally caused by shifts in the intensity and location of the East Asian summer monsoon (EASM). However, our knowledge of these EASM variations is limited, especially since the middle Holocene. We investigated two aeolian sedimentary sections (the Linxia/LX and Gulang/GL sections) on the western Chinese Loess Plateau (CLP), to explore the variations in the intensity and location of the EASM and their impact on the regional environment and human cultural development during the middle to late Holocene. The longitudes of these two loess sections are similar, but the GL section is located on the northern edge of the CLP, in the eastern Hexi Corridor, and it is situated further north than the LX section. The chronologies of both sections are based on accelerator mass spectrometry C-14 dating, and environmental magnetic parameters and grain size end-members were used to reconstruct their moisture histories. The results suggest that the climate at the LX section was relatively dry before 3.5 ka, after which it became wetter. In contrast, at the GL section, the climate was also relatively dry before 3.5 ka, with the wettest conditions occurring during 3.5-2 ka, but subsequently there was an abrupt shift to a dry climate. We suggest that these spatiotemporal patterns reflect the westward movement and rapid southward retreat of the EASM and the linked monsoon rainfall belt. TraCE-21 ka climate simulation results support our inference. We also found that, compared with other ancient cultures in the eastern Hexi Corrido, sites of the Shajing culture, dated to similar to 2.4-2.8 ka, are predominantly located in areas that are arid at the present-day, and relatively distant from rivers. We suggest that this distribution pattern reflected the occurrence of a humid climate during the period of the Shajing culture, thus demonstrating the impact of the EASM on cultural development in this region.
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| 5. |
- Liu, Heng, et al.
(författare)
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Defect Management and Ion Infiltration Barrier Enable High-Performance Perovskite Solar Cells
- 2024
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Ingår i: ACS Energy Letters. - 2380-8195. ; 9:6, s. 2790-2799
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Tidskriftsartikel (refereegranskat)abstract
- The stability of perovskite solar cells (PSCs) has been considered as one of the major obstacles toward practical application. Defects in the perovskite layer and ion infiltration from the hole transport layer (HTL) can trigger degradation of n-i-p PSCs. Herein, phenylhydrazine-4-sulfonic acid (PHPA) was employed as an additive to modulate perovskite crystallization during film formation, enlarging the perovskite crystal grain sizes to ∼3 μm. Density functional theory (DFT) calculations revealed that PHPA could effectively inhibit the formation of iodine vacancies (VI) and passivate the under-coordinated Pb2+ ions. Additionally, perfluorooctanoic acid (PFOA) was adopted to passivate the surface located dangling Pb2+ defects, improve the surface hydrophobicity, and inhibit Li+ ion migration from the HTL to the bottom perovskite, thus enhancing the device’s environmental and operational stability. Consequently, the resulting devices delivered a champion efficiency of 25.1% with an excellent maximum-power-point (MPP) tracking stability.
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| 6. |
- Xu, Zian, et al.
(författare)
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Hydrophobic-aerophilic composite catalysts enable the fast-charging Zn-air battery to operate 1200 h at 50 mA cm−2
- 2024
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Ingår i: Chemical Engineering Journal. - 1385-8947 .- 1873-3212. ; 481
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Tidskriftsartikel (refereegranskat)abstract
- High-efficient bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are central to Zn-air batteries (ZABs). However, the bifunctional activity of catalysts is still unsatisfactory, which restricts the fast-charge performance of ZABs. In this work, we constructed a hydrophobic-aerophilic bifunctional catalyst, where CoFe nanoparticles (NPs) and single atoms (SAs) are separately loaded on zeolite imidazolate fame (ZIF)-derived carbon and hollow carbon tubes respectively (CoFe NP@SA). Thereinto, CoFe SAs are known to be highly active to ORR reaction. Moreover, the in-situ Raman illustrates that CoFe NPs are transformed to CoOOH and FeOOH by electrochemical reconstruction, which can boost the OER activity. Furthermore, the hydrophobic-aerophilic surface can repel water molecules to create abundant solid–liquid-gas three-phase reaction interfaces and expose active sites, which consequently promote the diffusion of reactive molecules/ions across the interface and the oxygen adsorption. Thus, the CoFe NP@SA catalyst exhibit an ultralow ORR/OER potential gap of 0.6 V. After assembled as zinc-air battery (ZAB), it demonstrates a low charge potential (2.09 V) under a high current density of 50 mA cm−2 with the 1200-hour durability. This strategy paves the way to realize the high-power-density and fast-charging ZABs.
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