Institution
University of Massachusetts Amherst
Education•Amherst Center, Massachusetts, United States•
About: University of Massachusetts Amherst is a education organization based out in Amherst Center, Massachusetts, United States. It is known for research contribution in the topics: Population & Galaxy. The organization has 37274 authors who have published 83965 publications receiving 3834996 citations. The organization is also known as: UMass Amherst & Massachusetts State College.
Papers published on a yearly basis
Papers
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TL;DR: The results demonstrate that a fine and balanced modification/design of chemical structure can make significant performance differences and that the performance of solution-processed small-molecule-based solar cells can be comparable to or even surpass that of their polymer counterparts.
Abstract: A series of acceptor-donor-acceptor simple oligomer-like small molecules based on oligothiophenes, namely, DRCN4T-DRCN9T, were designed and synthesized. Their optical, electrical, and thermal properties and photovoltaic performances were systematically investigated. Except for DRCN4T, excellent performances were obtained for DRCN5T-DRCN9T. The devices based on DRCN5T, DRCN7T, and DRCN9T with axisymmetric chemical structures exhibit much higher short-circuit current densities than those based on DRCN6T and DRCN8T with centrosymmetric chemical structures, which is attributed to their well-developed fibrillar network with a feature size less than 20 nm. The devices based on DRCN5T/PC71BM showed a notable certified power conversion efficiency (PCE) of 10.10% under AM 1.5G irradiation (100 mW cm(-2)) using a simple solution spin-coating fabrication process. This is the highest PCE for single-junction small-molecule-based organic photovoltaics (OPVs) reported to date. DRCN5T is a rather simpler molecule compared with all of the other high-performance molecules in OPVs to date, and this might highlight its advantage in the future possible commercialization of OPVs. These results demonstrate that a fine and balanced modification/design of chemical structure can make significant performance differences and that the performance of solution-processed small-molecule-based solar cells can be comparable to or even surpass that of their polymer counterparts.
766 citations
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01 Dec 2004TL;DR: Initial results from a computational study of intrinsically motivated reinforcement learning aimed at allowing artificial agents to construct and extend hierarchies of reusable skills that are needed for competent autonomy are presented.
Abstract: Psychologists call behavior intrinsically motivated when it is engaged in for its own sake rather than as a step toward solving a specific problem of clear practical value. But what we learn during intrinsically motivated behavior is essential for our development as competent autonomous entities able to efficiently solve a wide range of practical problems as they arise. In this paper we present initial results from a computational study of intrinsically motivated reinforcement learning aimed at allowing artificial agents to construct and extend hierarchies of reusable skills that are needed for competent autonomy.
766 citations
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TL;DR: Variable deposition of F– and Na+during the African Humid Period suggests rapidly fluctuating lake levels between ∼11.7 and 4 ka, which is coincident with the “First Dark Age,” the period of the greatest historically recorded drought in tropical Africa.
Abstract: Six ice cores from Kilimanjaro provide an ∼11.7-thousand-year record of Holocene climate and environmental variability for eastern equatorial Africa, including three periods of abrupt climate change: ∼8.3, ∼5.2, and ∼4 thousand years ago (ka). The latter is coincident with the “First Dark Age,” the period of the greatest historically recorded drought in tropical Africa. Variable deposition of F – and Na + during the African Humid Period suggests rapidly fluctuating lake levels between ∼11.7 and 4 ka. Over the 20th century, the areal extent of Kilimanjaro9s ice fields has decreased ∼80%, and if current climatological conditions persist, the remaining ice fields are likely to disappear between 2015 and 2020.
765 citations
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TL;DR: In this article, a solution-processed small-molecule solar cells with almost 100% internal quantum efficiency and a power conversion efficiency of 9% were reported, making use of a donor molecule called DRCN7T and use PC71BM as an acceptor.
Abstract: Solution-processed small-molecule solar cells with almost 100% internal quantum efficiency and a power conversion efficiency of 9% are reported. The cells make use of a donor molecule called DRCN7T and use PC71BM as an acceptor.
764 citations
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TL;DR: In this article, the authors showed that nanofilaments derived from natural amino acids can have metallic-like conductivity and showed that they can be used to construct a metallic conductivity network.
Abstract: Networks of nanofilaments derived from natural amino acids can have metallic-like conductivity.
764 citations
Authors
Showing all 37601 results
Name | H-index | Papers | Citations |
---|---|---|---|
George M. Whitesides | 240 | 1739 | 269833 |
Joan Massagué | 189 | 408 | 149951 |
David H. Weinberg | 183 | 700 | 171424 |
David L. Kaplan | 177 | 1944 | 146082 |
Michael I. Jordan | 176 | 1016 | 216204 |
James F. Sallis | 169 | 825 | 144836 |
Bradley T. Hyman | 169 | 765 | 136098 |
Anton M. Koekemoer | 168 | 1127 | 106796 |
Derek R. Lovley | 168 | 582 | 95315 |
Michel C. Nussenzweig | 165 | 516 | 87665 |
Alfred L. Goldberg | 156 | 474 | 88296 |
Donna Spiegelman | 152 | 804 | 85428 |
Susan E. Hankinson | 151 | 789 | 88297 |
Bernard Moss | 147 | 830 | 76991 |
Roger J. Davis | 147 | 498 | 103478 |