| 1. |
- Fan, Qunping, et al.
(author)
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10.13% Efficiency All-Polymer Solar Cells Enabled by Improving the Optical Absorption of Polymer Acceptors
- 2020
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In: Solar RRL. - : Wiley. - 2367-198X. ; 4:6
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Journal article (peer-reviewed)abstract
- The limited light absorption capacity for most polymer acceptors hinders the improvement of the power conversion efficiency (PCE) of all-polymer solar cells (all-PSCs). Herein, by simultaneously increasing the conjugation of the acceptor unit and enhancing the electron-donating ability of the donor unit, a novel narrow-bandgap polymer acceptor PF3-DTCO based on an A–D–A-structured acceptor unit ITIC16 and a carbon–oxygen (C–O)-bridged donor unit DTCO is developed. The extended conjugation of the acceptor units from IDIC16 to ITIC16 results in a red-shifted absorption spectrum and improved absorption coefficient without significant reduction of the lowest unoccupied molecular orbital energy level. Moreover, in addition to further broadening the absorption spectrum by the enhanced intramolecular charge transfer effect, the introduction of C–O bridges into the donor unit improves the absorption coefficient and electron mobility, as well as optimizes the morphology and molecular order of active layers. As a result, the PF3-DTCO achieves a higher PCE of 10.13% with a higher short-circuit current density (Jsc) of 15.75 mA cm−2 in all-PSCs compared with its original polymer acceptor PF2-DTC (PCE = 8.95% and Jsc = 13.82 mA cm−2). Herein, a promising method is provided to construct high-performance polymer acceptors with excellent optical absorption for efficient all-PSCs.
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| 2. |
- Kang, Shichang, et al.
(author)
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Linking atmospheric pollution to cryospheric change in the Third Pole region : current progress and future prospects
- 2019
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In: National Science Review. - : Oxford University Press (OUP). - 2095-5138 .- 2053-714X. ; 6:4, s. 796-809
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Research review (peer-reviewed)abstract
- The Tibetan Plateau and its surroundings are known as the Third Pole (TP). This region is noted for its high rates of glacier melt and the associated hydrological shifts that affect water supplies in Asia. Atmospheric pollutants contribute to climatic and cryospheric changes through their effects on solar radiation and the albedos of snow and ice surfaces; moreover, the behavior and fates within the cryosphere and environmental impacts of environmental pollutants are topics of increasing concern. In this review, we introduce a coordinated monitoring and research framework and network to link atmospheric pollution and cryospheric changes (APCC) within the TP region. We then provide an up-to-date summary of progress and achievements related to the APCC research framework, including aspects of atmospheric pollution's composition and concentration, spatial and temporal variations, trans-boundary transport pathways and mechanisms, and effects on the warming of atmosphere and changing in Indian monsoon, as well as melting of glacier and snow cover. We highlight that exogenous air pollutants can enter into the TP's environments and cause great impacts on regional climatic and environmental changes. At last, we propose future research priorities and map out an extended program at the global scale. The ongoing monitoring activities and research facilitate comprehensive studies of atmosphere-cryosphere interactions, represent one of China's key research expeditions to the TP and the polar regions and contribute to the global perspective of earth system science.
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| 3. |
- Li, Chaoliu, et al.
(author)
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14C characteristics of organic carbon in the atmosphere and at glacier region of the Tibetan Plateau
- 2022
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In: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 832
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Journal article (peer-reviewed)abstract
- As an important component of carbonaceous aerosols (CA), organic carbon (OC) exerts a strong, yet insufficiently constrained perturbation of the climate. In this study, we reported sources of OC based on its natural abundance radiocarbon (14C) fingerprinting in aerosols and water-insoluble organic carbon (WIOC) in snowpits across the Tibetan Plateau (TP) – one of the remote regions in the world and a freshwater reservoir for billions of people. Overall, the proportions from 14C-based non-fossil fuel contribution (fnon-fossil) for OC in aerosols was 74 ± 10%, while for WIOC in snowpits was 81 ± 10%, both of which were significantly higher than that of elemental carbon (EC). These indicated sources of OC (WIOC) and EC were different at remote TP. Spatially, high fnon-fossil of WIOC of snowpit samples appeared at the inner part of the TP, indicating the important contribution of local non-fossil sources. Therefore, local non-fossil sources rather than long-range transportation OC dominants its total amount of the TP. In addition, the contribution of local non-fossil sourced WIOC increased during the monsoon period because heavy precipitation removed a high ratio of long-range transportation WIOC. The results of this study showed that not only OC and EC but also their different fuel sources should be treated separately in models to investigate their sources and atmospheric transportation.
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| 4. |
- Li, Chaoliu, et al.
(author)
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Sources of black carbon to the Himalayan-Tibetan Plateau glaciers
- 2016
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In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 7
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Journal article (peer-reviewed)abstract
- Combustion-derived black carbon (BC) aerosols accelerate glacier melting in the Himalayas and in Tibet (the Third Pole (TP)), thereby limiting the sustainable freshwater supplies for billions of people. However, the sources of BC reaching the TP remain uncertain, hindering both process understanding and efficient mitigation. Here we present the source-diagnostic Delta C-14/delta C-13 compositions of BC isolated from aerosol and snowpit samples in the TP. For the Himalayas, we found equal contributions from fossil fuel (46 +/- 11%) and biomass (54 +/- 11%) combustion, consistent with BC source fingerprints from the Indo-Gangetic Plain, whereas BC in the remote northern TP predominantly derives from fossil fuel combustion (66 +/- 16%), consistent with Chinese sources. The fossil fuel contributions to BC in the snowpits of the inner TP are lower (30 +/- 10%), implying contributions from internal Tibetan sources (for example, yak dung combustion). Constraints on BC sources facilitate improved modelling of climatic patterns, hydrological effects and provide guidance for effective mitigation actions.
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| 5. |
- Wu, Haimei, et al.
(author)
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Effects of the Isomerized Thiophene-Fused Ending Groups on the Performances of Twisted Non-Fullerene Acceptor-Based Polymer Solar Cells
- 2020
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In: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 12:21, s. 23904-23913
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Journal article (peer-reviewed)abstract
- Recently, benefiting from the merits of small-molecule acceptors (NFAs), polymer solar cells (PSCs) have achieved tremendous advances. From the perspective of the structural characteristics of the pi-conjugated acceptor-donor-acceptor (A-D-A) type of organic molecules, the backbones planarity and the terminal groups and their substituents have strong influences on the performances of the constructed NFAs. Through enlarging the dihedral angle of the conjugated main chain of NFAs, a certain degree of enhancement of photovoltaic parameters has been achieved. To further probe the influences of ending groups on the performances of nonplanar NFAs, we synthesized two new NFAs i-cc23 and i-cc34 with isomerized thiophene-fused ending groups and a twisted pi-conjugated main chain. Compared to i-cc23 containing the 2-(6-oxo-5,6-dihydro-4H-cyclopenta[b]thiophen-4-ylidene)malononitrile ending group, the acceptor i-cc34 containing 2-(6-oxo-5,6-dihydro-4H-cyclopenta[c]thiophen-4-ylidene)malononitrile has a relatively higher molar extinction coefficient, bathochromic-shifted absorption spectrum, and deepened energy levels. When mixed with PBDB-T in solar cells, the i-cc23-based device achieved an excellent open-circuit voltage (V-OC) of 1.10 V and a moderate power conversion efficiency of 7.34%. Although the V-OC of the i-cc34-related device was decreased to 0.96 V, the short-circuit current density and fill factor were improved, giving rise to an enhanced efficiency of 9.51%. Apart from the distinct photovoltaic performances, the two isomer-based devices exhibit a high radiative efficiency of 8 x 10(-4), leading to a very small nonradiative loss of 0.19 V. Our results emphasize the importance of the isomerized thiophene-fused ending groups on the performances of nonplanar NFA-based PSCs.
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