Aimed at achieving ideal morphology, illuminating morphology-performance relationship, and further improving the power conversion efficiency (PCE) of ternary polymer solar cells (TSCs), a ternary system is designed ba...
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Aimed at achieving ideal morphology, illuminating morphology-performance relationship, and further improving the power conversion efficiency (PCE) of ternary polymer solar cells (TSCs), a ternary system is designed based on PTB7-Th: PffBT4T-2OD:PC71BM in this work. The PffBT4T-2OD owns large absorption cross section, proper energy levels, and good crystallinity, which enhances exciton generation, charge dissociation and transport and suppresses charge recombination, thus remarkably increasing the short-circuit current density (J(sc)) and fill factor (FF). Finally, a notable PCE of 10.72% is obtained for the TSCs with 15% weight ratio of PffBT4T-2OD. As for the working mechanism, it confirmed the energy transfer from PffBT4T-2OD to PTB7-Th, which contributes to the improved exciton generation. And morphology characterization indicates that the devices with 15% PffBT4T-2OD possess both appropriate domain size (25 nm) and enhanced domain purity. Under this condition, it affords numerous D/A interface for exciton dissociation and good bicontinuous nanostructure for charge transport simultaneously. As a result, the device with 15% PffBT4T-2OD exhibits improved exciton generation, enhanced charge dissociation possibility, elevated hole mobility and inhibited charge recombination, leading to elevated Jsc (19.02 mA cm(-2)) and FF (72.62%) simultaneously. This work indicates that morphology optimization as well as energy transfer plays a significant role in improving TSC performance.
Self‐doped and crown‐ether functionalized fullerene PCMI:K+ works well as a cathode buffer layer in polymer solar cells based on PTB7‐Th, with a power conversion efficiency (PCE) of 10.30%, which is one of the high...
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Self‐doped and crown‐ether functionalized fullerene PCMI:K+ works well as a cathode buffer layer in polymer solar cells based on PTB7‐Th, with a power conversion efficiency (PCE) of 10.30%, which is one of the highest PCEs to date. A series of experiments are used to shed light upon the mechanism of the simultaneous elevation in photovoltaic parameters with PCMI:K+. [ABSTRACT FROM AUTHOR]
The structure evolution of oligomer fused-ring electron acceptors (FREAs) toward high efficiency of as-cast polymer solar cells (PSCs) is reported. First, a series of FREAs (IC-(1-3)IDT-IC) based on indacenodithiophen...
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The structure evolution of oligomer fused-ring electron acceptors (FREAs) toward high efficiency of as-cast polymer solar cells (PSCs) is reported. First, a series of FREAs (IC-(1-3)IDT-IC) based on indacenodithiophene (IDT) oligomers as cores are designed and synthesized, effects of IDT number (1-3) on their basic optical and electronic properties are investigated, and more importantly, the relationship between device performance of as-cast PSCs and donor(D)/acceptor(A) matching (absorption, energy level, morphology, and charge transport) of IC-(1-3) IDT-IC acceptors and two representative polymer donors, PTB7-Th and PDBT-T1 is surveyed. Then, the most promising D/A system (PDBT-T1/IC-1IDT-IC) with the best D/A harmony among the six D/A combinations, which yields a power conversion efficiency (PCE) of 7.39%, is found. Finally, changing the side-chains in IC-1IDT-IC from alkylphenyl to alkyl enhances the PCE from 7.39% to 9.20%.
We collected data on habitat use and locomotion of the François’langur(Trachypithecus francoisi)between August 2003 and July 2004 at Nonggang Nature Reserve,China.A total of 739 h of behavioral data were collect...
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We collected data on habitat use and locomotion of the François’langur(Trachypithecus francoisi)between August 2003 and July 2004 at Nonggang Nature Reserve,China.A total of 739 h of behavioral data were collected during this *** tested 2 predictions:(1)that the langurs may have special patterns of habitat use and locomotion adaptive to the limestone habitat,and(2)the langurs may exhibit different patterns of habitat use and locomotion among different zones of limestone *** results indicated that François’langurs spent more time in the low-risk,relatively food-poor cliff-hilltop *** young leaves and fruit were scarce in the dry season,the langurs increased their time in the high-risk,food-rich valley ***çois’langurs were semi-terrestrial,and leaping and climbing were their main locomotor *** behavioral patterns are considered to be related to characteristics of topography and vegetation in limestone habitat,such as large areas of cliff and discontinuous *** results also supported Prediction *** langurs confined locomotion to the main canopy and frequently adopted leaping while traveling in the hillside and valley *** traveling in cliff-hilltop areas,they tended to stay in the lower stratus(≤5 m)or move on the ground,and walking and climbing were their dominant traveling modes.
Anthropogenic factors affect biodiversity and have led to the contraction or extinction of animal populations ***,we use historical demographic data,spanning the past 300 years,to show that a rapid distributional cont...
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Anthropogenic factors affect biodiversity and have led to the contraction or extinction of animal populations ***,we use historical demographic data,spanning the past 300 years,to show that a rapid distributional contraction of giant pandas took place during the 18th and 19th centuries alongside the increase in human ***-use also underwent a significant change across the areas where giant pandas were found because of government agricultural policy and the introduction of new *** impact of social development on giant pandas includes habitat loss and fragmentation,and range *** findings would facilitate the design of effective conservation strategies that seek to conserve and increase current habitats of this iconic species,especially in areas that our analysis has identified as places where pandas have suffered from high human pressure.
We develop an efficient fused-ring electron acceptor (ITIC-Th) based on indacenodithieno [3,2-b]-thiophene core and thienyl side-chains for organic solar cells (OSCs). Relative to its counterpart with phenyl side-chai...
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We develop an efficient fused-ring electron acceptor (ITIC-Th) based on indacenodithieno [3,2-b]-thiophene core and thienyl side-chains for organic solar cells (OSCs). Relative to its counterpart with phenyl side-chains (ITIC), ITIC-Th shows lower energy levels (ITIC-Th: HOMO = -5.66 eV, LUMO =-3.93 eV;ITIC: HOMO = -5.48 eV, LUMO =-3.83 eV) due to the a-inductive effect of thienyl side-chains, which can match with high-performance narrow-band-gap polymer donors and wide-band-gap polymer donors. ITIC-Th has higher electron mobility (6.1 X 10(-4) cm(2) V-1 s(-1)) than ITIC (2.6 X 10(-4) cm(2) V-1 s(-1)) due to enhanced intermolecular interaction induced by sulfur-sulfur interaction. We fabricate OSCs by blending ITIC-Th acceptor with two different low-band-gap and wide-band-gap polymer donors. In one case, a power conversion efficiency of 9.6% was observed, which rivals some of the highest efficiencies for single junction OSCs based on fullerene acceptors.
Sleeping site locations are important to free-ranging primate *** are strategically selected by primates so as to optimize security,comfort and foraging *** were collected on the distribution of sleeping sites of the ...
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Sleeping site locations are important to free-ranging primate *** are strategically selected by primates so as to optimize security,comfort and foraging *** were collected on the distribution of sleeping sites of the Yunnan snub-nosed monkey(Rhinopithecus bieti)between Sep 2005 and Sep 2006 at Gehuaqing in Baimaxueshan Nature Reserve,*** identified 54 sleeping sites,which were used 137 times during the study *** sleeping sites were distributed throughout the monkey group’s total home *** preferred certain sleeping sites over others:63%of the sleeping sites were used 2 or more times in 13 *** reused locations in an unpredictable long-term pattern,but avoided using the same sleeping site on consecutive *** reduce the time and energetic costs of travel,monkeys preferred sleeping near commonly used feeding *** recorded 124 feeding sites in the home range,which were used 174 times.A total of 27 sleeping sites were also feeding sites,and all remaining sleeping sites were close to feeding *** was a positive correlation between the intensity of use of sleeping sites and feeding *** present study suggests that the availability and the location of immediate sources of food is a key factor in the choice of sleeping sites.
The panda lineage dates back to the late Miocene and ultimately leads to only one extant species,the giant panda(Ailuropoda melanoleuca).Although global climate change and anthropogenic disturbances are recognized
The panda lineage dates back to the late Miocene and ultimately leads to only one extant species,the giant panda(Ailuropoda melanoleuca).Although global climate change and anthropogenic disturbances are recognized
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