A5046980570- Advanced Memory and Neural Computing
- Catalytic Processes in Materials Science
- Molecular Junctions and Nanostructures
- CO2 Reduction Techniques and Catalysts
- Catalysis and Oxidation Reactions
- Semiconductor materials and devices
- Radical Photochemical Reactions
- Electrochemical Analysis and Applications
- Organic Electronics and Photovoltaics
- Electronic and Structural Properties of Oxides
- Diamond and Carbon-based Materials Research
- Catalysis and Hydrodesulfurization Studies
- Magnetic and transport properties of perovskites and related materials
- Graphene research and applications
- Advanced ceramic materials synthesis
- Electrocatalysts for Energy Conversion
- Transition Metal Oxide Nanomaterials
- Boron and Carbon Nanomaterials Research
- Aluminum Alloys Composites Properties
- Fullerene Chemistry and Applications
- Ferroelectric and Piezoelectric Materials
- Catalytic Cross-Coupling Reactions
- Pharmaceutical and Antibiotic Environmental Impacts
- Sulfur Compounds in Biology
- Carbon dioxide utilization in catalysis
Brookhaven National Laboratory
2020-2021
Massachusetts Institute of Technology
1989-2020
Columbia University
2013-2015
Gwangju Institute of Science and Technology
2006-2007
Abstract Despite numerous organic semiconducting materials synthesized for photovoltaics in the past decade, fullerenes are widely used as electron acceptors highly efficient bulk-heterojunction solar cells. None of non-fullerene bulk heterojunction cells have achieved efficiencies high fullerene-based Design principles fullerene-free remain unclear field. Here we report examples helical molecular semiconductors that on par with fullerene derivatives We an 8.3% power conversion efficiency a...
We describe the design and synthesis of a new graphene ribbon architecture that consists perylenediimide (PDI) subunits fused together by ethylene bridges. created prototype series oligomers consisting dimer, trimer, tetramer. The steric congestion at fusion point between PDI units creates helical junctions, longer form ribbons. Thin films these active layer in n-type field effect transistors. UV-vis spectroscopy reveals emergence an intense long-wavelength transition From DFT calculations,...
Condensation of fac-Re(5,6-diamino-1,10-phenanthroline)(CO)3Cl to o-quinone edge defects on graphitic carbon surfaces generates graphite-conjugated rhenium (GCC-Re) catalysts that are highly active for CO2 reduction CO in acetonitrile electrolyte. X-ray photoelectron and absorption spectroscopies establish the formation surface-bound Re centers with well-defined coordination environments. GCC-Re species glassy display catalytic currents greater than 50 mA cm−2 96 ± 3% Faradaic efficiency...
Nonvolatile and reversible resistance switching of copper doped MoOx film was studied. Hysteretic-type resistive observed under dc. Reproducible over 106cycles alternative voltage pulses. Two states can be maintained for 25h at 85°C. The authors proved that might strongly related with the rupture generation multifilaments confirmed by spreading images a conducting atomic force microscope as well filamentary conduction double logarithmic plots. Based on x-ray photoelectron spectroscopy...
Glassy carbon electrodes were functionalized with redox-active moieties by condensation of o-phenylenediamine derivatives o-quinone sites native to graphitic surfaces. Electrochemical and spectroscopic investigations establish that these graphite-conjugated catalysts (GCCs) exhibit strong electronic coupling the electrode, leading electron transfer (ET) behavior diverges fundamentally from solution-phase or surface-tethered analogues. We find (1) ET is not observed between electrode a GCC...
This work explores the formation of well-defined molecular p-n junctions in solution-processed self-assembled heterojunction solar cells using dodecyloxy-substituted contorted hexabenzocoronene (12-c-HBC) as a donor material and phenyl-C(70)-butyric acid methyl ester (PC(70)BM) an acceptor. We find that 12-c-HBC molecules effectively assemble solution to form nested structure with ball-shaped PC(70)BM. The result is molecular-scale junction. When this junction embedded active films, we can...
Here we report the use of pulse radiolysis and spectroelectrochemistry to generate low-valent nickel intermediates relevant synthetically important Ni-catalyzed cross-coupling reactions interrogate their reactivities toward comproportionation oxidative addition processes. Pulse provided a direct means singly reduced [(dtbbpy)NiBr], enabling identification rapid Ni(0)/Ni(II) process taking place under electrolysis conditions. This approach also permitted measurement Ni(I) rates with...
Electrophilic high-valent metal ions are potent intermediates for the catalytic functionalization of methane, but in many cases, their high redox potentials make these difficult or impossible to access using mild stoichiometric oxidants derived from O2. Herein, we establish electrochemical oxidation as a versatile new strategy accessing methane monofunctionalization catalysts. We provide evidence simple PdSO4 concentrated sulfuric acid electrolytes generate putative Pd2III,III species an...
Non-natural photoenzymatic reactions reported to date have depended on the excitation of electron donor-acceptor complexes formed between substrates and cofactors within protein active sites facilitate transfer. While this mechanism has unlocked new reactivity, it limits types that can be involved in area catalysis. Here we demonstrate direct flavin hydroquinone "ene"-reductase enables participate reactions. We found by using photoexcitation these enzymes gain ability reduce acrylamides...
The efficient interconversion of electrical and chemical energy requires the intimate coupling electrons small-molecule substrates at catalyst active sites. In molecular electrocatalysis, molecule acts as a redox mediator which typically undergoes oxidation or reduction in separate step from substrate activation. These mediated pathways introduce high-energy intermediate, cap driving force for activation potential molecule, impede access to high rates low overpotentials. Here we show that...
We have investigated various doped metal oxides such as copper molybdenum oxide, Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> , ZrO aluminium ZnO, and Cu xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> for novel resistance memory applications. Compared with non-stoichiometric (Nb xmlns:xlink="http://www.w3.org/1999/xlink">5-x</sub> SrTiO ), show higher device yield. Moreover,...
High-valent Pd complexes are potent agents for the oxidative functionalization of inert C–H bonds, and it was previously shown that rapid electrocatalytic methane monofunctionalization could be achieved by electro-oxidation PdII to a critical dinuclear PdIII intermediate in concentrated or fuming sulfuric acid. However, structure this highly reactive, unisolable intermediate, as well structural basis its mechanism electrochemical formation, remained elusive. Herein, we use X-ray absorption...
Epitaxial Nb-doped SrTiO3 films grown on Si substrates for nonvolatile resistance memory applications were investigated. With a TiN buffer layer, high-quality epitaxial film was the substrate, which confirmed through x-ray diffraction and transmission electron microscopy. Compared with control sample silicon substrate without samples layer show good characteristics of high ratio, retention characteristics, uniformity. In terms process compatibility standard process, have potential use in...
Covalent chemical modification is a powerful strategy for endowing low-cost graphitic carbon substrates with designer functionality. However, the surface chemistry of complex, making it difficult to tailor materials molecular level precision. Herein, we establish new that generates strong aromatic linkages surfaces. In particular, show condensation amidine-containing molecules oxidic edge defects on surfaces well-defined pyrimidine and imidazole linkages. X-ray photoelectron nitrogen K-edge...
ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionNEXTORIGINAL ARTICLEThis notice is a correctionCorrection to "Using Self-Organization To Control Morphology in Molecular Photovoltaics"Seok Ju Kang, Seokhoon Ahn, Jong Bok Kim, Christine Schenck, Anna M. Hiszpanski, Seokjoon Oh, Theanne Schiros, Yueh-Lin Loo, and Colin Nuckolls*Cite this: J. Am. Chem. Soc. 2013, 135, 28, 10579Publication Date (Web):July 9, 2013Publication History Published online9 July 2013Published inissue 17...
We evaluated the resistive switching effect of polycrystalline oxide (Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> , ZrO xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> and Cr-SrTiO xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ) fabricated by reactive sputtering PLD. It shows a well-developed behavior. The reproducible resistance cycles were observed ratio was as high...
Ultrashallow junction (<l0nm) p <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> /n formed by B <inf xmlns:xlink="http://www.w3.org/1999/xlink">18</inf> H xmlns:xlink="http://www.w3.org/1999/xlink">22</inf> cluster ion implantation and excimer laser annealing (ELA) is demonstrated. equivalent energy at 0.25 keV readily forms an amorphous-silicon (a-Si) layer without additional Si or Ge implantation. After ELA 500 mJ/cm...
The structural and electrical properties of Nb-doped heteroepitaxial structure prepared by a pulsed laser deposition system were characterized. Using X-ray diffraction analysis transmission electron microscopy, it was confirmed that the films on silicon epitaxially grown. Based Rutherford backscattering spectroscopy study, relatively high density defects such as oxygen vacancies observed in film. exhibits rectifying current-voltage (I-V) characteristics, large hysteresis I-V characteristics...
The resistance switching of several oxides has been reported for nonvolatile memory applications (NVM), recently. However, the mechanisms have not yet clearly understood, and uniformity reproducibility devices are sufficient gigabit NVM applications. In this paper, we investigated electrical characteristics various binary ternary NVM. First, non- stoichiometric polycrystalline (Nb2O5, ZrOx) evaluated. Subsequently, resistive CuxO heavily Cu doped MoOx film compatibility to modern CMOS....
Ultrashallow junction (<l0nm) p <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> /n formed by B <inf xmlns:xlink="http://www.w3.org/1999/xlink">18</inf> H xmlns:xlink="http://www.w3.org/1999/xlink">22</inf> cluster ion implantation and excimer laser annealing (ELA) is demonstrated. equivalent energy at 0.25 keV readily forms an amorphous-silicon (a-Si) layer without additional Si or Ge implantation. After ELA 500 mJ/cm...