| 1. |
- Zhang, Jianyun, et al.
(författare)
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Revealing the Critical Role of the HOMO Alignment on Maximizing Current Extraction and Suppressing Energy Loss in Organic Solar Cells
- 2019
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Ingår i: iScience. - : Cell Press. - 2589-0042. ; 19, s. 883-893
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Tidskriftsartikel (refereegranskat)abstract
- For state-of-the-art organic solar cells (OSCs) consisting of a large-bandgap polymer donor and a near-infrared (NIR) molecular acceptor, the control of the HOMO offset is the key to simultaneously achieve small energy loss (Eloss) and high photocurrent. However, the relationship between HOMO offsets and the efficiency for hole separation is quite elusive so far, which requires a comprehensive understanding on how small the driving force can effectively perform the charge separation while obtaining a high photovoltage to ensure high OSC performance. By designing a new family of ZITI-X NIR acceptors (X = S, C, N) with a high structural similarity and matching them with polymer donor J71 forming reduced HOMO offsets, we systematically investigated and established the relationship among the photovoltaic performance, energy loss, and hole-transfer kinetics. We achieved the highest PCEavgs of 14.05 ± 0.21% in a ternary system (J71:ZITI-C:ZITI-N) that best optimize the balance between driving force and energy loss.
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| 2. |
- Lin, Li'na, et al.
(författare)
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GEOCHRONOLOGIC AND GEOCHEMICAL EVIDENCE FOR PERSISTENCE OF SOUTH-DIPPING SUBDUCTION TO LATE PERMIAN TIME, LANGSHAN AREA, INNER MONGOLIA (CHINA) : SIGNIFICANCE FOR TERMINATION OF ACCRETIONARY OROGENESIS IN THE SOUTHERN ALTAIDS
- 2014
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Ingår i: American Journal of Science. - : American Journal of Science (AJS). - 0002-9599 .- 1945-452X. ; 314:2, s. 679-703
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Tidskriftsartikel (refereegranskat)abstract
- The Langshan area in Inner Mongolia is situated in the southern Altaids between the Beishan suture to the west and the Solonker suture to the east. This paper addresses the poorly known tectonic evolution that led to formation of the terminal Solonker suture. Dating of deformed porphyries and undeformed dolerites and gabbros constrains the timing of the relevant NE-E-striking and north-vergent deformation. Deformed granitic-granodioritic porphyries in this area are characterized by high SiO2 (65.38-78.00%), low TFe2O3 (1.29-5.07%), MgO (0.13-0.63%), and variable K2O (0.534.14%) and Na2O (2.05-4.62%). All samples have enriched LREE (La/Yb 6-18) and negative Nb anomalies (Nb-N/Th(N)0.09-0.48), but different Eu anomalies (Eu* <0.7 or similar to 1); these geochemical features can be ascribed to a heterogeneous source in a subduction-related environment. Gabbros and dolerites have 42.33 to 52.03 percent SiO2. All mafic samples have similar La/Yb ratios of 4 to 6 and negative Nb anomalies (Nb-N/Th-N) ratios of 0.2 to 0.8, suggestive of a subduction-related setting. Two granitic porphyries yielded U-238/Pb-206 weighted mean ages of 284.7 +/- 2.1 Ma with MSWD of 1.6 and 291.7 +/- 2: 2.1 Ma with MSWD of 1.14; these ages are consistent with U-235/Pb-207 and U-238/Pb-206 concordia ages of 281 +/- 17 Ma with MSWD of 0.87 and 289.8 +/- 9.2 Ma with MSWD of 0.66. A dolerite yielded concordia ages of 256.2 +/- 2.6 Ma with MSWD of 0.44 and 256 +/- 2.5 Ma with MSWD 0.45. The ages and geochemistry of the deformed porphyries indicate that in the early Permian there was important deformation and recrystallization in a subduction-related setting. The isotopic and geochemical signatures of all the rocks indicate that they formed during subduction-related conditions. We propose that Langshan was a Permian active continental margin arc built on the edge of the North China Craton by southward subduction, which led to closure of the ocean, concomitant formation of the Solonker suture in the late Permian-early Triassic, and termination of the accretion-subduction orogen of the southern Altaids.
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| 3. |
- Liu, Yanfeng, et al.
(författare)
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Electric Field Facilitating Hole Transfer in Non-Fullerene Organic Solar Cells with a Negative HOMO Offset
- 2020
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Ingår i: The Journal of Physical Chemistry C. - : AMER CHEMICAL SOC. - 1932-7447 .- 1932-7455. ; 124:28, s. 15132-15139
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Tidskriftsartikel (refereegranskat)abstract
- The record high photoinduced current and power conversion efficiencies of organic solar cells (OSCs) should be attributed to the significant contribution of non-fullerene electron acceptors via hole transfer to electron donors and/or a pronounced decrease in energy losses for exciton dissociation by aligned highest occupied molecular orbitals (HOMOs) or lowest unoccupied molecular orbitals (LUMOs). However, the hole transfer mechanism in those highly efficient non-fullerene OSCs with small HOMO offsets has not been extensively studied and fully understood, yet. Herein, we comparatively study the hole transfer kinetics in two OSCs with a positive (0.05 eV) and a negative (-0.07 eV) HOMO offset (Delta HOMO) based on polymer donor PTQ10 paired with non-fullerene acceptors ZITI-C or ZITI-N. Short-circuit current densities (J(sc)) of 20.42 and 12.81 mA cm(-2) are achieved in the OSCs based on PTQ10:ZITI-C (Delta HOMO = 0.05 eV) and PTQ10:ZITI-N (Delta HOMO = -0.07 eV) with an optimized donor (D):acceptor (A) ratio of 1:1, respectively, despite the small and even negative Delta HOMO. Results from time-resolved transient absorption spectroscopy show slower hole transfer (14.3 ps) in PTQ10:ZITI-N than that (3.7 ps) in PTQ10:ZITI-C. To understand the decent J(sc) value in the OSCs of PTQ10:ZITI-N, the temperature and electric field dependences of hole transfer are investigated in low-donor-content OSCs (D:A ratio of 1:9) in which photocurrent is dominated by the contribution via hole transfer from ZITI-N to PTQ10. Devices based on PTQ10:ZITI-C and PTQ10:ZITI-N show similar free charge generation behavior as a function of temperature, whereas the external quantum efficiencies of the PTQ10:ZITI-N device exhibit a much stronger bias dependence than that of PTQ10:ZITI-C, which suggests that the electric field facilitates exciton dissociation in PTQ10:ZITI-N where the energetic driving force alone cannot efficiently dissociate excitons.
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| 4. |
- Zhou, Zichun, et al.
(författare)
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Subtle Molecular Tailoring Induces Significant Morphology Optimization Enabling over 16% Efficiency Organic Solar Cells with Efficient Charge Generation
- 2020
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Ingår i: Advanced Materials. - : WILEY-V C H VERLAG GMBH. - 0935-9648 .- 1521-4095. ; 32:4
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Tidskriftsartikel (refereegranskat)abstract
- Manipulating charge generation in a broad spectral region has proved to be crucial for nonfullerene-electron-acceptor-based organic solar cells (OSCs). 16.64% high efficiency binary OSCs are achieved through the use of a novel electron acceptor AQx-2 with quinoxaline-containing fused core and PBDB-TF as donor. The significant increase in photovoltaic performance of AQx-2 based devices is obtained merely by a subtle tailoring in molecular structure of its analogue AQx-1. Combining the detailed morphology and transient absorption spectroscopy analyses, a good structure-morphology-property relationship is established. The stronger pi-pi interaction results in efficient electron hopping and balanced electron and hole mobilities attributed to good charge transport. Moreover, the reduced phase separation morphology of AQx-2-based bulk heterojunction blend boosts hole transfer and suppresses geminate recombination. Such success in molecule design and precise morphology optimization may lead to next-generation high-performance OSCs.
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| 5. |
- Chen, Cheng, et al.
(författare)
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Triple collocation-based error estimation and data fusion of global gridded precipitation products over the Yangtze River basin
- 2022
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Ingår i: Journal of Hydrology. - : Elsevier BV. - 0022-1694. ; 605
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Tidskriftsartikel (refereegranskat)abstract
- Error estimation and data fusion are critical to improving the accuracy of global model- and satellite-based precipitation products for practical applications. However, they face challenges over vast areas of the world due to limited ground observations. Triple collocation (TC) method can overcome this limitation and provide an efficient way for error estimation without the “ground truth” and thus also for data fusion, by leveraging multi-source observations and model outputs, which have been increasingly available in recent years. In this work, we conducted a comprehensive study on error estimation and data fusion of a number of global gridded precipitation products over the Yangtze River basin from 2015 to 2018 using TC and multiplicative TC (MTC) methods. We use three satellite-based precipitation products such as the IMERG Final (IMERG-F), PERSIANN-CDR (PCDR) and SM2RAIN-ASCAT (SM2R), and one reanalysis dataset ERA5 which contains precipitation estimates. They were grouped into two TC triplets based on different combinations: IMERG-F + SM2R + ERA5 and PCDR + SM2R + ERA5. For performance evaluation, the TC-based error estimation methods were compared to the traditional method using rain gauge data, and the TC-based data fusion methods were compared with two widely-used data fusion methods Bayesian Model Averaging (BMA) and Random Forest based MErging Procedure (RF-MEP). Results showed that ERA5 had the best performance with the largest correlation coefficient (CC, 0.435), while PCDR had the worst accuracy with the smallest CC (0.304) and the largest absolute relative bias (RB, 0.365). TC tended to underestimate the root mean square error (RMSE) with respect to the traditional gauged-based method, but MTC showed a consistent result owing to the employment of a multiplicative error model. The performance of TC-based data fusion methods had no significant difference from BMA and RF-MEP. All data fusion results were better than the original triplets, as the mean CC value increased from 0.38 to 0.47 and the mean RMSE decreased from 15.0 to 13.5 mm/day. In addition, we found that the zero value replacement in MTC had great influence on error estimation, while had limited impacts on data fusion.
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| 6. |
- Liu, Feng, et al.
(författare)
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Modulating Structure Ordering via Side-Chain Engineering of Thieno[3,4-b]thiophene-Based Electron Acceptors for Efficient Organic Solar Cells with Reduced Energy Losses
- 2019
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Ingår i: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 11:38, s. 35193-35200
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Tidskriftsartikel (refereegranskat)abstract
- Nonfullerene-based organic solar cells (OSCs) have made a huge breakthrough in the recent years. Introducing a proper side chain on the pi-conjugated backbone plays a vital role for further improving the power conversion efficiency (PCE) of OSCs due to easy tuning of the physical properties of the molecule such as absorption, energetic level, solid-state stacking, and charge transportation. More importantly, the side chain significantly affected the blend films morphology and thus determined the PCEs of the devices. In this work, two low-band-gap nonfullerene acceptors, ATT-4 and ATT-5, with an alkyl or branched alkyl substitute on indacenodithiophene (IDT) and thieno[3,4-b]thiophene (TbT) backbone were synthesized for investigating the effect of the substituent on the performance of the nonfullerene acceptors (NFAs). In comparison to ATT-1 with p-hexylphenyl-substituted IDT and n-octyl-substituted TbT moieties, ATT-4 and ATT-5 exhibit better crystallinity with shorter interchain distance and ordered molecular structure in neat and the corresponding blend films. The tailored ATT-5 exhibits a high PCE of 12.36% with a V-oc of 0.93 V, J(sc) of 18.86 mA cm(-2), and fill factor (FF) of 0.71, blending with a wide-band-gap polymer donor PBDB-T. Remarkably, although ATT-4 and ATT-5 exhibit broader light absorption, the devices obtained higher V-oc than that of ATT-1 mainly due to the reduced nonradiative recombination in the blend films. These results implied that side-chain engineering is an efficient approach to regulate the electronic structure and molecular packing of NFAs, which can well match with polymer donor, and obtain high PCEs of the OSCs with improved V-oc, J(sc), and FF, simultaneously.
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| 7. |
- Ning, Zhongrui, et al.
(författare)
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Wetter trend in source region of Yangtze River by runoff simulating based on Grid-RCCC-WBM
- 2024
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Ingår i: Journal of Hydrology. - 0022-1694. ; 631
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Tidskriftsartikel (refereegranskat)abstract
- Exploring the future hydroclimatic conditions of source region of Yangtze River (SRYaR), an alpine affected by climate change significantly, is essential for basin water resources management and development ss global climate change intensifies and the process of climate warming and humidification in Northwest China. This study proposed a practical framework for assessing water resource response to the context of climate changes in alpine catchments from the respective of both runoff and hydroclimatic conditions. Utilizing Grid-RCCC-WBM driven by corrected climatic forcing from the global climate models, this study estimate the prospective overall warmer and wetter pattern in the source region of Yangtze River. The key results indicated that: (1) Under all future scenarios, both temperature and precipitation within the catchment exhibit a significant upward trend. Projections from multi-model ensembles (MME) suggest that during the mid-term period (2041–2060, MT), temperatures are expected to rise by [0.74 °C, 3.08 °C] compared to the baseline period (1995–2014), with precipitation changes ranging from [4.8%, 21.4%]. (2) Future runoff within the catchment exhibits a consistent increase, with a linear trend rate of 1.1 mm/decade. runoff changes in MT compared to the baseline period vary from [−5.1%, 33.7%]. Runoff decreases in the northern part of the catchment, while notable increases occur in the southeastern and western regions. (3) In the future, the ratio of catchment evaporation capacity to precipitation decreases in comparison to the baseline period with an augmentation in soil moisture, enhancing its capacity for water retention and reducing the conversion of precipitation to evaporation, resulting a wetting trend of the catchment. (4) The future snowpack in the catchment continues to decrease, with a significant reduction in both the proportion of snowfall relative to total precipitation and the proportion of snowmelt runoff relative to total runoff, the risk of water resources crisis in the watershed is escalating.
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| 8. |
- Sun, Jiaqi, et al.
(författare)
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Water-Energy-Food integrated management model under Uncertainty-A case study of Yulin City
- 2023
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Ingår i: Journal of Hydrology. - 0022-1694 .- 1879-2707. ; 625
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Tidskriftsartikel (refereegranskat)abstract
- Water, energy, and food are indispensable human survival and development resources. With the rapid development of the social economy, the systematic risk of water, energy, and food is becoming increasingly prominent. Water, energy, and food security are threatened to varying degrees. At the same time, water, energy, and food are interrelated, restricted, and interdependent. It is of great scientific significance to reveal and optimize the WEF (Water-Energy-Food) nexus. This study relied on Chance constrained programming and Fuzzy credibility constrained programming to deal with randomness and fuzziness in the WEF nexus. Meanwhile, based on Bi-level programming, aiming at minimizing water allocation and maximizing system benefits, a Water-Energy-Food Integrated Management Model to deal with multiple Uncertainties, called IMMU-WEF model was constructed. The model solved the critical effects of the randomness of water supply and the subjective fuzziness of water demand on water resources allocation, power generation, primary energy extraction, and food planting area. The results showed that the IMMU-WEF model could efficiently deal with the game between different departments in the resource management system, the random uncertainty expressed by probability density, and the fuzzy uncertainty caused by subjective factors. It can develop a stable management scheme for resource management. Applying the mode to Yulin City, China, it is found that water supply and demand fluctuation dramatically impacts on the WEF system benefit, water resources allocation, energy and food production. Specifically, the system benefit will increase over time, with a total benefit of 1974.04 × 108-1998.06 × 108 yuan (2021–2025), 3065.69 × 108-3100.50 × 108 yuan (2026–2030), and 4128.80 × 108-4191.07 × 108 yuan (2031–2035). Additionally, the system water allocation, primary energy extraction, power generation, and food planting are expected to increase over three time periods. With the increase of water supply in the future, the energy and food production in Yulin City show an increasing trend. It indicates that water shortage will continue to be a major problem in Yulin in the three periods, and that the city still needs to increase water supply and diversion projects to ensure energy security and food security. The results can provide an optimal management scheme for ensuring Yulin City’s water, energy, and food security.
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