245 research outputs found
Improving the photovoltaic response of a poly(3-octylthiophene)/n-Si heterojunction by incorporating double-walled carbon nanotubes
Poly(3-octylthiophene)/n-Si heterojunction solar cells were studied with and without incorporation of double-walled carbon nanotubes (DWCNs) in the polymer layer. The performance of the device improves significantly by the incorporation of DWCNs. We report a power conversion efficiency, open circuit voltage, short-circuit current density and fill factor of 0.49%, 0.53 V, 5.9 mA cm−2 and 0.15 respectively for an un-optimized cell containing DWCNs. Reference cells without DWCNs show a much lower performance. DWCN incorporation yields better hole transport, easy exciton splitting and suppression of charge recombination, thereby improving photovoltaic action. DWCN seems a promising material for improving hole transport in organic solar cells
Improving photovoltaic response of poly„3-hexylthiophene…/n-Si heterojunction by incorporating double walled carbon nanotubes
Poly(3-hexylthiophene)/n-Si heterojunction solar cells were studied with and without incorporation of double walled carbon nanotubes (DWCNs) in the polymer layer. Performance of the device improves by manyfold by incorporation of DWCN. The authors report power conversion efficiency, open circuit voltage, short-circuit current density, and fill factor of 0.026%, 0.446 V, 0.3398 mA/cm2, and 0.17, respectively, for an unoptimized cell containing DWCN. Reference cells without DWCNs show much lower performance. DWCN incorporation yields better hole transport, easy exciton splitting, and suppression of charge recombination, thereby improving photovoltaic action. DWCN seems promising materials for improving hole transport in organic solar cells
Field electron emission of double walled carbon nanotube film prepared by drop casting method
Thick films of double walled carbon nanotubes (DWCN) were deposited on indium-tin-oxide (ITO) coated glass substrates by drop casting method and were studied for their field electron emission property in a parallel plate configuration using bare ITO coated glass as counter electrode. They show excellent field electron emission property with low turn-on-field of about 0.8 V/lm and threshold field of about 1.8 V/lm. Field enhancement factor calculated from the non-saturated region of the FN plot is about 1715. Field electron emission current was observed to be stable up to 3000 min, indicating thereby that DWCNs are excellent electron emitters with appreciable stable performance
Volatile organic compounds are ghosts for organic solar cells
All our efforts to demonstrate a multifunctional device – photovoltaic gas sensor (i.e. solar cell which
show photovoltaic action depending on the gas / volatile organic compounds (VOC) in the surrounding
atmosphere) yielded negative results. Photovoltaic performance of the organic solar cells under study
degraded – almost permanently by exposing them to volatile organic compounds (VOCs). Although, the
proposed multifunctional device could not be demonstrated; Present investigations yielded very important
result that organic solar cells have problems not only with oxygen and humidity (known facts) but also
with many VOCs and hazardous gases – making lamination / encapsulation step mandatory for their practical
utilizatio
Fast and stable method for simulating quantum electron dynamics
A fast and stable method is formulated to compute the time evolution of a
wavefunction by numerically solving the time-dependent Schr{\"o}dinger
equation. This method is a real space/real time evolution method implemented by
several computational techniques such as Suzuki's exponential product, Cayley's
form, the finite differential method and an operator named adhesive operator.
This method conserves the norm of the wavefunction, manages periodic conditions
and adaptive mesh refinement technique, and is suitable for vector- and
parallel-type supercomputers. Applying this method to some simple electron
dynamics, we confirmed the efficiency and accuracy of the method for simulating
fast time-dependent quantum phenomena.Comment: 10 pages, 35 eps figure
Solution of the quantum inverse problem
We derive a formula that expresses the local spin and field operators of
fundamental graded models in terms of the elements of the monodromy matrix.
This formula is a quantum analogue of the classical inverse scattering
transform. It applies to fundamental spin chains, such as the XYZ chain, and to
a number of important exactly solvable models of strongly correlated electrons,
such as the supersymmetric t-J model or the the EKS model.Comment: 37 pages, AMS-Latex, AMS-Font
Madelung Fluid Model for The Most Likely Wave Function of a Single Free Particle in Two Dimensional Space with a Given Average Energy
We consider spatially two dimensional Madelung fluid whose irrotational
motion reduces into the Schr\"odinger equation for a single free particle. In
this respect, we regard the former as a direct generalization of the latter,
allowing a rotational quantum flow. We then ask for the most likely wave
function possessing a given average energy by maximizing the Shannon
information entropy over the quantum probability density. We show that there
exists a class of solutions in which the wave function is self-trapped,
rotationally symmetric, spatially localized with finite support, and spinning
around its center, yet stationary. The stationarity comes from the balance
between the attractive quantum force field of a trapping quantum potential
generated by quantum probability density and the repulsive centrifugal force of
a rotating velocity vector field. We further show that there is a limiting case
where the wave function is non-spinning and yet still stationary. This special
state turns out to be the lowest stationary state of the ordinary Schr\"odinger
equation for a particle in a cylindrical tube classical potential.Comment: 19 page
Trans-saccadic priming in hemianopia: sighted-field sensitivity is boosted by a blind-field prime
We experience visual stability despite shifts of the visual array across the retina produced by eye movements.
A process known as remapping is thought to keep track of the spatial locations of objects as they
move on the retina. We explored remapping in damaged visual cortex by presenting a stimulus in the
blind field of two patients with hemianopia. When they executed a saccadic eye movement that would
bring the stimulated location into the sighted field, reported awareness of the stimulus increased, even
though the stimulus was removed before the saccade began and so never actually fell in the sighted
field. Moreover, when a location was primed by a blind-field stimulus and then brought into the sighted
field by a saccade, detection sensitivity for near-threshold targets appearing at this location increased
dramatically. The results demonstrate that brain areas supporting conscious vision are not necessary
for remapping, and suggest visual stability is maintained for salient objects even when they are not
consciously perceived
Double-walled carbon nanotubes-incorporated donor–acceptor-type organic photovoltaic devices using poly(3-octylthiophene) and C60
Donor–acceptor-type photovoltaic devices with a heterojunction between regioregular poly(3-octylthiophene) (P3OT) and C60 are fabricated with and without the addition of double-walled carbon nanotubes (DWCNs) in the polymer layer. Incorporation of DWCNs in the polymer layer improves the performance of the device by many folds, which is attributable to improved exciton dissociation and better charge transport leading to the suppression of charge carrier recombination. We report an opencircuit voltage, short-circuit current density, fill factor and conversion efficiency (%) of approximately 0.37 V, 0.014 mA/cm2,0.22 and 0.001%, respectively, for an unoptimized device incorporating DWCNs
The Schr\"oder functional equation and its relation to the invariant measures of chaotic maps
The aim of this paper is to show that the invariant measure for a class of
one dimensional chaotic maps, , is an extended solution of the Schr\"oder
functional equation, , induced by them. Hence, we give an
unified treatment of a collection of exactly solved examples worked out in the
current literature. In particular, we show that these examples belongs to a
class of functions introduced by Mira, (see text). Moreover, as a new example,
we compute the invariant densities for a class of rational maps having the
Weierstrass functions as an invariant one. Also, we study the relation
between that equation and the well known Frobenius-Perron and Koopman's
operators.Comment: 9 page
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