The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Feng Wang - One of the best experts on this subject based on the ideXlab platform.
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ultrafast Charge Transfer in atomically thin mos2 ws2 heterostructures
Nature Nanotechnology, 2014Co-Authors: Xiaoping Hong, Jonghwan Kim, Sufei Shi, Yu Zhang, Chenhao Jin, Yinghui Sun, Sefaattin Tongay, Yanfeng Zhang, Feng WangAbstract:The Charge Transfer between two layers of different two-dimensional materials occurs at a much faster speed than expected, holding promise for efficient optoelectronic devices.
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ultrafast Charge Transfer in atomically thin mos2 ws2 heterostructures
Nature Nanotechnology, 2014Co-Authors: Xiaoping Hong, Jonghwan Kim, Sufei Shi, Yu Zhang, Chenhao Jin, Yinghui Sun, Sefaattin Tongay, Yanfeng Zhang, Feng WangAbstract:The Charge Transfer between two layers of different two-dimensional materials occurs at a much faster speed than expected, holding promise for efficient optoelectronic devices. Van der Waals heterostructures have recently emerged as a new class of materials, where quantum coupling between stacked atomically thin two-dimensional layers, including graphene, hexagonal-boron nitride and transition-metal dichalcogenides (MX2), give rise to fascinating new phenomena1,2,3,4,5,6,7,8,9,10. MX2 heterostructures are particularly exciting for novel optoelectronic and photovoltaic applications, because two-dimensional MX2 monolayers can have an optical bandgap in the near-infrared to visible spectral range and exhibit extremely strong light–matter interactions2,3,11. Theory predicts that many stacked MX2 heterostructures form type II semiconductor heterojunctions that facilitate efficient electron–hole separation for light detection and harvesting12,13,14,15,16. Here, we report the first experimental observation of ultrafast Charge Transfer in photoexcited MoS2/WS2 heterostructures using both photoluminescence mapping and femtosecond pump–probe spectroscopy. We show that hole Transfer from the MoS2 layer to the WS2 layer takes place within 50 fs after optical excitation, a remarkable rate for van der Waals coupled two-dimensional layers. Such ultrafast Charge Transfer in van der Waals heterostructures can enable novel two-dimensional devices for optoelectronics and light harvesting.
Xiaoping Hong - One of the best experts on this subject based on the ideXlab platform.
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ultrafast Charge Transfer in atomically thin mos2 ws2 heterostructures
Nature Nanotechnology, 2014Co-Authors: Xiaoping Hong, Jonghwan Kim, Sufei Shi, Yu Zhang, Chenhao Jin, Yinghui Sun, Sefaattin Tongay, Yanfeng Zhang, Feng WangAbstract:The Charge Transfer between two layers of different two-dimensional materials occurs at a much faster speed than expected, holding promise for efficient optoelectronic devices.
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ultrafast Charge Transfer in atomically thin mos2 ws2 heterostructures
Nature Nanotechnology, 2014Co-Authors: Xiaoping Hong, Jonghwan Kim, Sufei Shi, Yu Zhang, Chenhao Jin, Yinghui Sun, Sefaattin Tongay, Yanfeng Zhang, Feng WangAbstract:The Charge Transfer between two layers of different two-dimensional materials occurs at a much faster speed than expected, holding promise for efficient optoelectronic devices. Van der Waals heterostructures have recently emerged as a new class of materials, where quantum coupling between stacked atomically thin two-dimensional layers, including graphene, hexagonal-boron nitride and transition-metal dichalcogenides (MX2), give rise to fascinating new phenomena1,2,3,4,5,6,7,8,9,10. MX2 heterostructures are particularly exciting for novel optoelectronic and photovoltaic applications, because two-dimensional MX2 monolayers can have an optical bandgap in the near-infrared to visible spectral range and exhibit extremely strong light–matter interactions2,3,11. Theory predicts that many stacked MX2 heterostructures form type II semiconductor heterojunctions that facilitate efficient electron–hole separation for light detection and harvesting12,13,14,15,16. Here, we report the first experimental observation of ultrafast Charge Transfer in photoexcited MoS2/WS2 heterostructures using both photoluminescence mapping and femtosecond pump–probe spectroscopy. We show that hole Transfer from the MoS2 layer to the WS2 layer takes place within 50 fs after optical excitation, a remarkable rate for van der Waals coupled two-dimensional layers. Such ultrafast Charge Transfer in van der Waals heterostructures can enable novel two-dimensional devices for optoelectronics and light harvesting.
Phaedon Avouris - One of the best experts on this subject based on the ideXlab platform.
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self aligned carbon nanotube transistors with Charge Transfer doping
arXiv: Materials Science, 2005Co-Authors: Jia Chen, Christian Klinke, Ali Afzali, Phaedon AvourisAbstract:This letter reports a Charge Transfer p-doping scheme which utilizes one-electron oxidizing molecules to obtain stable, unipolar carbon nanotube transistors with a self-aligned gate structure. This doping scheme allows one to improve carrier injection, tune the threshold voltage Vth, and enhance the device performance in both the ON- and OFF- transistor states. Specifically, the nanotube transistor is converted from ambipolar to unipolar, the device drive current is increased by 2-3 orders of magnitude, the device OFF current is suppressed and an excellent Ion/Ioff ratio of six order of magnitude is obtained. The important role played by metal-nanotube contacts modification through Charge Transfer is demonstrated.
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self aligned carbon nanotube transistors with Charge Transfer doping
Applied Physics Letters, 2005Co-Authors: Jia Chen, Christian Klinke, Ali Afzali, Phaedon AvourisAbstract:This letter reports a Charge Transfer p-doping scheme which utilizes one-electron oxidizing molecules to obtain stable, unipolar carbon nanotube transistors with a self-aligned gate structure. This doping scheme allows one to improve carrier injection, tune the threshold voltage Vth, and enhance the device performance in both the “ON-” and “OFF-” transistor states. Specifically, the nanotube transistor is converted from ambipolar to unipolar, the device drive current is increased by 2–3 orders of magnitude, the device OFF current is suppressed and an excellent Ion∕Ioff ratio of 106 is obtained. The important role played by metal–nanotube contacts modification through Charge Transfer is demonstrated.
Kentsung Wong - One of the best experts on this subject based on the ideXlab platform.
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exciplex an intermolecular Charge Transfer approach for tadf
ACS Applied Materials & Interfaces, 2018Co-Authors: Monima Sarma, Kentsung WongAbstract:Organic materials that display thermally activated delayed fluorescence (TADF) are a striking class of functional materials that have witnessed a booming progress in recent years. In addition to pure TADF emitters achieved by the subtle manipulations of intramolecular Charge Transfer processes with sophisticated molecular structures, a new class of efficient TADF-based OLEDs with emitting layer formed by blending electron donor and acceptor molecules that involve intermolecular Charge Transfer have also been fabricated. In contrast to pure TADF materials, the exciplex-based systems can realize small ΔEST (0–0.05 eV) much more easily since the electron and hole are positioned on two different molecules, thereby giving small exchange energy. Consequently, exciplex-based OLEDs have the prospective to maximize the TADF contribution and achieve theoretical 100% internal quantum efficiency. Therefore, the challenging issue of achieving small ΔEST in organic systems could be solved. In this article, we summarize...
Dominik B Bucher - One of the best experts on this subject based on the ideXlab platform.
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uv induced Charge Transfer states in short guanosine containing dna oligonucleotides
ChemBioChem, 2020Co-Authors: Corinna L Kufner, Wolfgang Zinth, Dominik B BucherAbstract:: Charge Transfer has proven to be an important mechanism in DNA photochemistry. In particular, guanine (dG) plays a major role as an electron donor, but the photophysical dynamics of dG-containing Charge-Transfer states have not been extensively investigated so far. Here, we use UV pump (266 nm) and picosecond IR probe (∼5-7 μm) spectroscopy to study ultrafast dynamics in dG-containing short oligonucleotides as a function of sequence and length. For the pure purine oligomers, we observed lifetimes for the Charge-Transfer states of the order of several hundreds of picoseconds, regardless of the oligonucleotide length. In contrast, pyrimidine-containing dinucleotides d(GT) and d(GC) show much faster relaxation dynamics in the 10 to 30 ps range. In all studied nucleotides, the Charge-Transfer states are formed with an efficiency of the order of ∼50 %. These photophysical characteristics will lead to an improved understanding of DNA damage and repair processes.
