Conformationally controlled ultrafast intersystem crossing in bithiophene systems

2018 ◽  
Vol 20 (19) ◽  
pp. 13412-13418 ◽  
Author(s):  
Anders B. Skov ◽  
Martin A. B. Larsen ◽  
Mikkel B. Liisberg ◽  
Thorsten Hansen ◽  
Theis I. Sølling
Keyword(s):  
Solar Cell ◽  
Molecular Electronics ◽  
Model Systems ◽  
Intersystem Crossing

Bithiophenes serve as model systems for polythiophenes used in solar cell applications and molecular electronics. Bithiophene has two major conformations, where the disfavored cis-conformation shows a higher rate of intersystem crossing.

Research Highlights

COSMOS ◽  
2011 ◽  
Vol 07 (01) ◽  
pp. 5-10
Keyword(s):  
Solar Cell ◽  
Molecular Electronics ◽  
Graphene Quantum Dots ◽  
Dye Sensitized Solar Cell ◽  
Dye Sensitized ◽  
Non Volatile Memory ◽  
Parallel Configuration ◽  
Hybrid Devices ◽  
Memory Applications ◽  
Water Supply Safety

A Colorful Spin on Silk. Transforming C60 Molecules into Graphene Quantum Dots. Molecular Electronics. Wafer-scale Graphene/Ferroelectric Hybrid Devices for Non-volatile Memory Applications. A Single Dye-Sensitized Solar Cell of Parallel Configuration. Using Ferns to Clean up Arsenic-Tainted Water for Food and Water Supply Safety.

Porphyrin-based nanostructures: routes to molecular electronics

2000 ◽  
Vol 04 (04) ◽  
pp. 401-406 ◽  
Author(s):  
ANTHONY K. BURRELL ◽  
MICHAEL R. WASIELEWSKI
Keyword(s):  
Molecular Electronics ◽  
Light Harvesting ◽  
Three Dimensional ◽  
Electronic System ◽  
Reaction Centers ◽  
Model Systems ◽  
Molecular Electronic

The potential of porphyrins and related macrocycles for applications in molecular electronics owes much to the fundamental studies of the photosynthetic light-harvesting arrays and reaction centers. The use of model systems to better understand these essential processes has resulted in the development of an assortment of methodologies for functionalizing and constructing the complex three-dimensional nanostructures that will be essential for a successful molecular electronic system.

Transmission Electron Microscopy of Evaporated Perylene Thin Films

1990 ◽  
Vol 48 (2) ◽  
pp. 336-337
Author(s):  
C. Ewins ◽  
J.R. Fryer
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Molecular Electronics ◽  
High Vacuum ◽  
Amorphous Layer ◽  
Electric Heater ◽  
Transmission Electron ◽  
Polycyclic Aromatic

The preparation of thin films of organic molecules is currently receiving much attention because of the need to produce good quality thin films for molecular electronics. We have produced thin films of the polycyclic aromatic, perylene C10H12 by evaporation under high vacuum onto a potassium chloride (KCl) substrate. The role of substrate temperature in determining the morphology and crystallography of the films was then investigated by transmission electron microscopy (TEM).The substrate studied was the (001) face of a freshly cleaved crystal of KCl. The temperature of the KCl was controlled by an electric heater or a cold finger. The KCl was heated to 200°C under a vacuum of 10-6 torr and allowed to cool to the desired temperature. The perylene was then evaporated over a period of one minute from a molybdenum boat at a distance of 10cm from the KCl. The perylene thin film was then backed with an amorphous layer of carbon and floated onto copper microscope grids.

Nuclear coiled bodies and the nucleolus

1994 ◽  
Vol 52 ◽  
pp. 20-21
Author(s):  
K. Brasch ◽  
J. Williams ◽  
D. Gallo ◽  
T. Lee ◽  
R. L. Ochs
Keyword(s):  
Mouse Liver ◽  
Nuclear Body ◽  
Nuclear Bodies ◽  
Model Systems ◽  
Coiled Body ◽  
Rrna Processing ◽  
Malignant Cells ◽  
Sm Proteins ◽  
Coiled Bodies ◽  
Unique Protein

Though first described in 1903 by Ramon-y-Cajal as silver-staining “accessory bodies” to nucleoli, nuclear bodies were subsequently rediscovered by electron microscopy about 30 years ago. Nuclear bodies are ubiquitous, but seem most abundant in hyperactive and malignant cells. The best studied type of nuclear body is the coiled body (CB), so termed due to characteristic morphology and content of a unique protein, p80-coilin (Fig.1). While no specific functions have as yet been assigned to CBs, they contain spliceosome snRNAs and proteins, and also the nucleolar protein fibrillarin. In addition, there is mounting evidence that CBs arise from or are generated near the nucleolus and then migrate into the nucleoplasm. This suggests that as yet undefined links may exist, between nucleolar pre-rRNA processing events and the spliceosome-associated Sm proteins in CBs.We are examining CB and nucleolar changes in three diverse model systems: (1) estrogen stimulated chick liver, (2) normal and neoplastic cells, and (3) polyploid mouse liver.

Microtubule Dynamics and Organelle Transport in Reticulomyxa

1990 ◽  
Vol 48 (3) ◽  
pp. 194-195
Author(s):  
Yih-Tai Chen ◽  
Ursula Euteneuer ◽  
Ken B. Johnson ◽  
Michael P. Koonce ◽  
Manfred Schliwa
Keyword(s):  
Plasma Membrane ◽  
Light Microscopy ◽  
Cytoplasmic Dynein ◽  
Living Cells ◽  
Microtubule Dynamics ◽  
Model Systems ◽  
Organelle Transport ◽  
Biochemical Characteristics ◽  
Dependent Transport

The application of video techniques to light microscopy and the development of motility assays in reactivated or reconstituted model systems rapidly advanced our understanding of the mechanism of organelle transport and microtubule dynamics in living cells. Two microtubule-based motors have been identified that are good candidates for motors that drive organelle transport: kinesin, a plus end-directed motor, and cytoplasmic dynein, which is minus end-directed. However, the evidence that they do in fact function as organelle motors is still indirect.We are studying microtubule-dependent transport and dynamics in the giant amoeba, Reticulomyxa. This cell extends filamentous strands backed by an extensive array of microtubules along which organelles move bidirectionally at up to 20 μm/sec (Fig. 1). Following removal of the plasma membrane with a mild detergent, organelle transport can be reactivated by the addition of ATP (1). The physiological, pharmacological and biochemical characteristics show the motor to be a cytoplasmic form of dynein (2).

Microstructural observations of the “Wustite-Spinel” coexistence following quenching of cation-excess spinels, Ni2(1+x)Ti1-xO4

1990 ◽  
Vol 48 (4) ◽  
pp. 1058-1059
Author(s):  
Ian M. Anderson ◽  
Arnulf Muan ◽  
C. Barry Carter
Keyword(s):  
Film Growth ◽  
Spinel Phase ◽  
Model Systems ◽  
Ion Milling ◽  
Coexistence Of Phases ◽  
Nonequilibrium Conditions ◽  
Diffraction Patterns ◽  
Spinel Structures ◽  
Highly Porous ◽  
Standard Techniques

Oxide mixtures which feature a coexistence of phases with the wüstite and spinel structures are considered model systems for the study of solid-state reaction kinetics, phase boundaries, and thin-film growth, and such systems are especially suited to TEM studies. (In this paper, the terms “wüstite” and “spinel” will refer to phases of those structure types.) The study of wüstite-spinel coexistence has been limited mostly to systems near their equilibrium condition, where the assumptions of local thermodynamic equilibrium are valid. The cation-excess spinels of the type Ni2(1+x)Ti1-xO4, which reportedly exist only above 1375°C4, provide an excellent system for the study of wüstite-spinel coexistence under highly nonequilibrium conditions. The nature of these compounds has been debated in the literature. X-ray and neutron powder diffraction patterns have been used to advocate the existence of a single-phase, non- stoichiometric spinel. TEM studies of the microstructure have been used to suggest equilibrium coexistence of a stoichiometric spinel, Ni2TiO4, and a wüstite phase; this latter study has shown a coexistence of wüstite and spinel phases in specimens thought to have been composed of a single, non- stoichiometric spinel phase. The microstructure and nature of this phase coexistence is the focus of this study. Specimens were prepared by ball-milling a mixture of NiO and TiO2 powders with 10 wt.% TiO2. The mixture was fired in air at 1483°C for 5 days, and then quenched to room temperature. The aggregate thus produced was highly porous, and needed to be infiltrated prior to TEM sample preparation, which was performed using the standard techniques of lapping, dimpling, and ion milling.

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