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Found in: ključnih besedah
Summary of found: ...QCD, fizika visokih energij, Monte Carlo generator, ...
Keywords: QCD, fizika visokih energij, Monte Carlo generator
Published: 15.10.2013; Views: 4256; Downloads: 17
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Found in: ključnih besedah
Summary of found: ...QCD, partoni, Monte Carlo generator, ...
Keywords: QCD, partoni, Monte Carlo generator
Published: 15.10.2013; Views: 3861; Downloads: 21
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Found in: ključnih besedah
Summary of found: ... Monte Carlo simulation, biopolymers, coil-globule transition, Wang-Landau sampling,...
Keywords: Monte Carlo simulation, biopolymers, coil-globule transition, Wang-Landau sampling
Published: 25.04.2014; Views: 4954; Downloads: 17
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Abstract: The electric-charge transport in organic semiconductors is essentially different to the transport in ordered inorganic crystals. The reason is in thelocalization of the energy states, which act as charge-carrier transport channels between molecules. Consequently, the determination of the basic transport parameters in organic materials is inherently more involved than in their inorganic counterparts. The analytical methods that are used to describe charge transport in inorganic materials are unsuitable, since they are based on the extended electronic energy structure. We report here on the simulation of charge transport in organic semiconductor thin films. The simulation is based on the Monte Carlo method and describes the charge-carrier transport within the framework of carrier hopping between the sites. We employed a Gaussian energy distribution of the hopping sites with disorder elements. The degree of disorder is characterized by the width of the Gaussian distribution and is measured in eV units. The results of the transport simulation in 3,4,9,10-perylenedianhydride tetracarboxylic acid (PTCDA) show that the photogenerated charge-carrier current depends on the film thickness, temperature and disorder degree. The simulated photocurrents have the same amplitude in thick films as in the thin films, but the overall shape of the I(t) curve is more dispersive in thin films. The charge-carrier mobility decreases with the increasing degree of disorder at a given temperature. The simulation of the photogenerated positive charge carriers current matches with the time-of-flight experiment in a glass/ITO/PTCDA(600 nm)/In heterostructure at room temperature and an applied bias voltage of 8 V.
Found in: ključnih besedah
Keywords: neurejeni kristali, metoda Monte Carlo, organski polprevodniki, transport naboja, PTCDA, tranzientne meritve
Published: 10.07.2015; Views: 5026; Downloads: 17
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Abstract: We use a micro-canonical Wang–Landau technique to study the equilibrium properties of a single flexible homopolymer where consecutive monomers are represented by impenetrable hard spherical beads tangential to each other, and non-consecutive monomers interact via a square-well potential. To mimic the characteristics of a protein-like system, the model is then refined in two different directions. Firstly, by allowing partial overlap between consecutive beads, we break the spherical symmetry and thus provide a severe constraint on the possible conformations of the chain. Alternatively, we introduce additional spherical beads at specific positions in the direction normal to the backbone, to represent the steric hindrance of the side chains in real proteins. Finally, we consider also a combination of these two ingredients. In all three systems, we obtain the full phase diagram in the temperature-interaction range plane and find the presence of helicoidal structures at low temperatures in the intermediate range of interactions. The effect of the range of the square-well attraction is highlighted, and shown to play a role similar to that found in simple liquids and polymers. Perspectives in terms of protein folding are finally discussed.
Found in: ključnih besedah
Summary of found: ...Wang-Landau approach, Monte-Carlo simulations, proteins, secondary structures...
Keywords: Wang-Landau approach, Monte-Carlo simulations, proteins, secondary structures
Published: 04.05.2016; Views: 3322; Downloads: 0
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