Cyclopropano[70]fullerenes have been synthesized in the aim of being used as acceptors in blends based on regioregular poly (3,5-Hexylthiophene) RR-P3HT for photovoltaic (PV) plastic cells. These molecules used with RR-P3HT in bulk heterojunction (BHJ) configuration provided interesting characteristics: 1.5% solar conversion efficiency, 9.29 mA/cm2 current density, 0.51 V open circuit voltage, and 0.34 fill factor. The IPCE spectrum for P3HT: cyclopropano[70]fullerene cells shows a peak around 430 nm with 71% external quantum efficiency. This result justifies the increased current density.
The optical and electrical properties of bulk polymer RR-P3HT (Regio-Regular Poly(3-hexylthiophène-2,5-
diyl):PCBM (Methanofullerene Phenyl-C61-Butyric-Acid-Methyl-Ester) heterojunction incorporating single wall
carbon nanotubes (SWCNTs) have been already reported by a number of research groups. We investigated a new
approach to functionalize CarboLex single wall carbon nanotubes (SWCNTs-e) for increasing their dispersion in
various solvents. The addition of SWCNTs-e in the matrix of P3HT:PCBM improves the photovoltaic (PV)
characteristics.
Results show that the photovoltaic parameters depend on the concentration of SWCNTs-e. The incorporation of low
concentrations of SWCNTs-e in the photoactive layer increases the current density Jsc before annealing.
We attribute the improved performance to partial crystallisation of the RR-P3HT. As revealed by XRD studies and
confirmed by the absorbance spectra which exhibit the characteristic 600 nm shoulder. Interestingly, we observed
also that doping the P3HT:PCBM system with the functionalized SWCNTs increases Voc from 0.583 to 0.744 V.
The optical and electrical properties of bulk polymer RR-P3HT (Regio-Regular Poly(3-hexylthiophène-2,5-
diyl):PCBM (Methanofullerene Phenyl-C61-Butyric-Acid-Methyl-Ester) heterojunction incorporating single wall
carbon nanotubes (SWCNTs) have been already reported by a number of research groups.
We investigated a new approach to functionalize CarboLex single wall carbon nanotubes (SWCNTs-e) for
increasing their dispersion in various solvents. The addition of SWCNTs-e in the matrix of P3HT:PCBM improves
the photovoltaic (PV) characteristics.
Results show that the photovoltaic parameters depend on the concentration of SWCNTs-e. The incorporation of
low concentrations of SWCNTs-e in the photoactive layer increases the current density Jsc before annealing.
We attribute the improved performance to partial crystallisation of the RR-P3HT. As revealed by XRD studies and
confirmed by the absorbance spectra which exhibit the characteristic 600 nm shoulder. Interestingly, we
observed also that doping the P3HT:PCBM system with the functionalized SWCNTs increases Voc from 0.583 to
0.744 V.
Experimental and numerical results concerning the influence of silver nanoparticles on the optical absorption of organic
devices are presented. The metallic nanoparticles (NPs) are placed inside an interpenetrated poly(3-hexylthiophene):
[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) layer using a physical vapor deposition technique. An
absorption enhancement by comparison to devices without NPs is shown. An increase of the absorption by annealing is
also observed. Moreover, calculations are performed via a numerical analysis based on a Finite Difference Time Domain
(FDTD) method. We demonstrate that the light absorption can mainly occur inside the active layer instead of inside the
metallic NPs.
Depending on the minimum size of their micro/nano structure, thin films can exhibit very different behaviors and optical
properties. From optical waveguides down to artificial anisotropy, through diffractive optics and photonic crystals, the
application changes when decreasing the minimum feature size.
Rigorous electromagnetic theory can be used to model most of the components but when the size is of a few nanometers,
quantum theory has also to be used. These materials including quantum structures are of particular interest for other
applications, in particular for solar cells, because of their luminescent and electronic properties.
We show that the properties of electrons in multiple quantum wells can be easily modeled with a formalism similar to
that used for multilayer waveguides. The effects of different parameters, in particular coupling between wells and well
thickness dispersion, on possible discrete energy levels or energy band of electrons and on electron wave functions is
given. When such quantum confinement appears the spectral absorption and the extinction coefficient dispersion with
wavelength is modified. The dispersion of the real part of the refractive index can then be deduced from the Kramers-
Krönig relations. Associated with homogenization theory this approach gives a new model of refractive index for thin
films including quantum dots. Absorption spectra of samples composed of ZnO quantum dots in PMMA layers are in
preparation are given.
Experimental investigations of two-photon absorption (TPA)
cross-section using nonlinear transmission (NLT) and a
new pump-probe mode-mismatched thermal lens (TL) scheme, in the picosecond regime are reported. Both methods are
used in a prospect of comparison. Values of the TPA coefficient and cross-section in perylenediimide derivatives (PDI)
at 532 nm and 1064 nm wavelengths are given.
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