Electrical behavior, simulation

The preceding sections described molecular interactions important in organic solar cells. This section discusses the impact of those interactions on the overall device behavior. Simulated electrical behavior for a typical solar cell is illustrated in Fig. 10. Under forward bias voltages 0 < V < Vqo typical photovoltaic device under illumination supplies power (P = / x V) to the external circuit (cf. lower panel of Fig. 10, dashed trace in first quadrant). The formalism used here implies that, under reverse bias, the organic material is reduced at the anode and oxidized at the cathode, while, under forward bias, the organic material is oxidized at the anode and reduced at the cathode. The short circuit current, J c, is approximately equal to... 

Fig. 10 Simulated solar cell electrical behavior in the dark dotted traces) and under illumination (solid traces) comparing the effect of the saturation current parameter 7 on Foe- The black traces represent a device with /g x 10 that of the device represented by the red traces. The sharp inflection points in the semilog plots (upper panel) are the points where the current switches from positive to negative. Also illustrated in the linear representation (lower panel) are the short circuit current density, J c, and the maximum output power, Fmax. given by the product of current and voltage. The blue arrows represent the point at which the dark current and the current under illumination are equal in magnitude. The corresponding potential marked in blue on the voltage axis is Foe for the black trace...

The models commonly used to simulate the mechanical and electrical behavior of piezoelectric transducers generally introduce simplifying assumptions that are often invalid for actual designs [57]. The geometries of practical transducers are often two-(2-D) or three-dimensional (3-D) [58]. Simulations of piezoelectric media require the... 

Henriquez, C.S. 1993. Simulating the electrical behavior of cardiac tissue using the bidomain model. Crit. Rev. Biomed. Eng. 21 1-77. 

Most of the new molecular-level results concern the structure and dynamics of water at interfaces. We begin this review with a brief summary of this area. Several recent review articles and books can be consulted for additional information. " We then examine in some detail the new insight gained from molecular dynamic simulations of the structure of the electric double layer and the general behavior of ions at the water/metal interface. We conclude by examining recent developments in the modeling of electron transfer reactions. 

The kinetics data of the geminate ion recombination in irradiated liquid hydrocarbons obtained by the subpicosecond pulse radiolysis was analyzed by Monte Carlo simulation based on the diffusion in an electric field [77,81,82], The simulation data were convoluted by the response function and fitted to the experimental data. By transforming the time-dependent behavior of cation radicals to the distribution function of cation radical-electron distance, the time-dependent distribution was obtained. Subsequently, the relationship between the space resolution and the space distribution of ionic species was discussed. The space distribution of reactive intermediates produced by radiation is very important for advanced science and technology using ionizing radiation such as nanolithography and nanotechnology [77,82]. 

Two runs at high CO2 concentrations (9.8 mole percent CO2/ N2/5A 1/4" and 13.2 mole percent C02/air/5A 1/8" LMS pellets), for which it was determined that effects of heat transfer could be very important, were run in a special column designed by F. W. Leavitt (developer of the MASC program) to simulate essentially adiabatic behavior. The column was constructed of thin-walled sheet metal and was 24.8 cm in diameter. Electric heating jackets placed in sections along the wall of the column and controlled by thermocouples placed at corresponding intervals along the centerline of the bed were used to maintain the wall at essentially the same temperature as the bed interior. 

Experiments to measure the electric field and water polarization within 10 A of the surface are difficult to perform. However, recent Molecular Dynamics simulations carried out by Faraudo and Bresme for water between two sodium dodecyl sulfate layers revealed oscillatory behaviors for both the polarization and the electric fields near the surface, and non-proportionality between them [Faraudo, J. Bresme, F. Phys. Rev. Lett. 2004, 92, 236102], Our polari-... 

Recent molecular dynamics simulations of water between two surfactant (sodium dodecyl sulfate) layers, reported by Faraudo and Bresme,14 revealed oscillatory behaviors for both the polarization and the electric fields near a surface and that the two fields are not proportional to each other. While the nonmonotonic behavior again invalidated the Gruen—Marcelja model for the polarization, the nonproportionality suggested that a more complex dielectric response of water might, be at the origin of the hydration force. The latter conclusion was also supported by recent molecular dynamics simulations of Far audo and Bresme, who reported interactions between surfactant surfaces with a nonmonotonic dependence on distance.15... 

A model calculation predicted an anomalous dielectric behavior of water in the vicinity of a surface and an oscillatory dependence on distance of the water polarization and the electric potential in the close vicinity of a surface, which are very similar to the results obtained via molecular dynamics simulations.14... 

The second difficulty can be removed if one assumes that in the vicinity of an interface the water is organized in icelike layers. The electrical interactions between the water dipoles of successive layers lead indeed to an oscillatory behavior of the polarization [35], If the surface is not perfectly flat, of if the water is not perfectly organized in water layers, the statistical average smooth out the polarization oscillations [35], The latter results have been also supported by molecular dynamics simulation, in which the surface dipoles were allowed to move [36], Let us now examine in detail how the correlation between neighboring dipoles occurs. 

Matoba, Y., T. Hirota, J. Ohnishi, N. Murai and M. Matsuo (1994a). An indoor simulation of the behavior of insecticides supplied by an electric vaporizer, Chemosphere, 28, 435-451. 

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