Nanostructured Organic Thin Films: Electronic Energetics and Devices

2001 ◽  
Vol 15 (28n30) ◽  
pp. 3722-3726 ◽  
Author(s):  
C. TALIANI ◽  
F. BISCARINI ◽  
E. LUNEDEI ◽  
P. Mei ◽  
M. Muccini ◽  
...  
Keyword(s):  
Thin Films ◽  
Energy Transfer ◽  
Vibrational Spectroscopy ◽  
Crystal Packing ◽  
Organic Thin Films ◽  
Model Systems ◽  
Conjugation Length ◽  
Time Dynamics ◽  
Transfer Processes

We report on the optoelectronic properties of vacuum sublimed organic thin films of the oligothienyls ( Tn ) model systems. The Davydov splitting (DS) of the lowest exciton is about 0.3 eV and decreases with the conjugation length when going from T 4 to T 6. The lowest DS component is partially forbidden due to the crystal packing and the spectral activity occurs via Herzberg-Teller (HT) vibronic coupling. We show the real time dynamics of the HT coupling by coherent vibrational spectroscopy and the role of aggregates in the energy transfer processes within the films.

Light amplification in organic thin films using cascade energy transfer

Nature ◽  
10.1038/38979 ◽  
1997 ◽  
Vol 389 (6650) ◽  
pp. 466-469 ◽  
Author(s):  
M. Berggren ◽  
A. Dodabalapur ◽  
R. E. Slusher ◽  
Z. Bao
Keyword(s):  
Thin Films ◽  
Energy Transfer ◽  
Organic Thin Films ◽  
Light Amplification ◽  
Cascade Energy

scholarly journals Tuning Nanoscale Friction by Applying Weak Magnetic Fields to Reorient Adsorbed Oxygen Molecules

2018 ◽  
Vol 4 (1) ◽  
pp. 1 ◽  
Author(s):  
Z. Fredricks ◽  
K. Stevens ◽  
S. Kenny ◽  
B. Acharya ◽  
J. Krim
Keyword(s):  
Magnetic Field ◽  
Thin Films ◽  
Weak Magnetic Field ◽  
Quartz Crystal ◽  
Sliding Friction ◽  
Model Systems ◽  
Theoretical Studies ◽  
Weak Magnetic Fields ◽  
Gold Substrates

Sliding friction levels of thin (1–2 monolayers) and thick (~10 monolayers) oxygen films adsorbed on nickel and gold at 47.5 K have been measured by means of a quartz crystal microbalance (QCM) technique. Friction levels for the thin (thick) films on nickel in the presence of a weak magnetic field were observed to be approximately 30% (50%) lower than those recorded in the absence of the external field. Friction levels for thin films on gold were meanwhile observed to be substantially increased in the presence of the field. Magnetically-induced structural reorientation (magnetostriction) and/or realignment of adlayer spins, which respectively reduce structural and magnetic interfacial corrugation and commensurability, appear likely mechanisms underlying the observed field-induced reductions in friction for the nickel samples. Eddy current formation in the gold substrates may account for the increased friction levels in this system. The work demonstrates the role of magnetic effects in model systems that are highly amenable to theoretical studies and modeling.

Role of Ions in Bias Enhanced Nucleation of Diamond

1995 ◽  
Vol 388 ◽  
Author(s):  
J.M. Lannon ◽  
J.S. Gold ◽  
Cd. Stinespring
Keyword(s):  
Thin Films ◽  
Silicon Carbide ◽  
Surface Composition ◽  
Hydrogen Ions ◽  
Ion Energy ◽  
Transfer Processes ◽  
Ion Interactions ◽  
Ion Energies

AbstractIon-surface interactions are thought to play a role in bias enhanced nucleation of diamond. To explore this hypothesis and understand the mechanisms, surface studies of hydrogen and hydrocarbon ion interactions with silicon and silicon carbide have been performed. the experiments were carried out at room temperature and used in-situ auger analyses to monitor the surface composition of thin films produced or modified by the ions. Ion energies ranged from 10 to 2000 eV. Hydrogen ions were found to modify silicon carbide thin films by removing silicon and converting the resulting carbon-rich layers to a mixture of sp2- and sp3-C. the interaction of hydrocarbon ions with silicon was shown to produce a thin film containing SiC-, sp2-, and sp3-C species. IN general, the relative amount of each species formed was dependent upon ion energy, fluence, and mass. the results of these studies, interpreted in terms of chemical and energy transfer processes, provide key insights into the mechanisms of bias enhanced nucleation.

Effects of Crystal Packing on Photoinduced Proton-Transfer Processes of 2,4-Dinitrobenzylpyridine Derivatives

1997 ◽  
Vol 53 (2) ◽  
pp. 306-316 ◽  
Author(s):  
S. Khatib ◽  
M. Botoshansky ◽  
Y. Eichen
Keyword(s):  
Proton Transfer ◽  
Crystal Packing ◽  
Aromatic Rings ◽  
Proton Abstraction ◽  
Thermally Activated ◽  
Transfer Processes ◽  
Highly Sensitive ◽  
Photoinduced Proton Transfer ◽  
Photochemical Properties

Photoinduced and thermally activated proton-transfer processes taking place in crystals of 2-(2,4-dinitrobenzyl)pyridine and some of its derivatives are highly sensitive to molecular packing. Small differences in the way the molecules are packed in the crystal are found to dominate molecular properties in controlling the photoactivity of the different phototautomers, leading, for example, to photoactive or photoinert systems. Three compounds, 2-(2,4-dinitrobenzyl)-4-methylpyridine, 1-(2,4-dinitrophenyl)-l-(2-pyridine)ethane and 4′-(2,4-dinitrobenzyl)-4-methyl-2,2′-bipyridine, having different photochemical properties, were prepared and their crystal structures characterized by means of X-ray analysis. In the photoinert crystals the 2,4-dinitrophenyl group is π-stacked with other aromatic rings of neighboring molecules. This arrangement may open some deactivation channels to the excited state which are faster than the proton-transfer process, leading to photoinert crystals. The absence of π-stacking between the chromophore and other aromatic rings leads to photoactive systems. An O atom of the o-nitro group is the only basic atom that is systematically found to interact with the abstracted proton. It seems that this atom is responsible for the photoinduced proton abstraction of the benzylic H atom, while the role of the N atom of the pyridine ring in the proton-abstraction process is mainly inductive.

Reflectance anisotropy spectroscopy applied to organic thin films: The role of the substrate

2018 ◽  
Vol 62 ◽  
pp. 102-106
Author(s):  
A. Sassella ◽  
L. Raimondo ◽  
L. Fazi ◽  
S. Trabattoni ◽  
B. Bonanni ◽  
...  
Keyword(s):  
Thin Films ◽  
Organic Thin Films ◽  
Reflectance Anisotropy
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