It is shown that the introduction of functionalized single-walled carbon nanotubes SWNTs in bulk heterojunction
polymer-fullerene photovoltaic devices results in an improvement of both the short circuit current density and the fill
factor. An optimum performance with a power conversion efficiency of 1.4% is obtained with 0.5 wt% of SWNTs in a
(1:1) P3HT/PCBM mixture. The results indicate that the addition of nanotubes enhances the performance of polymerfullerene
photovoltaic cells by means of both the electron accepting feature of fullerenes and the high electron transport
capability of SWNTs.
Organic photovoltaics are the focus of intense research efforts due to the low-cost of processing and their
potential applications in flexible electronics. We herein report efficient, thick (2,500 Å) photovoltaic devices based on
ternary mixtures of polycarbonate linked TPD (N,N,N',N'-tetrakis(phenyl) benzidine)) polymer (PTPD), small
molecular weight radical salt of a TPD derivative and C60 in an ITO/blend/Al configurations. While the addition of
electron acceptor C60 moiety to PTPD produces a 3 orders more, short circuit current (Isc) of 0.22 mA/cm2, the presence of salt increased it further to 0.33 mA/cm2. This is attributed to the increased hole conductivity and absorption of PTPD matrix due to the presence of salt. In these 'PTPD/salt/C60' ternary blend devices, the fill factors as well as the power conversion efficiencies increased with increasing salt concentration with the highest fill factor of 0.4 and power conversion efficiency of 0.47% obtained in 10% salt doped ternary ITO/PTPD-salt-C60/Al device. To the best of our
knowledge this is the first time that a radical salt has been used into an organic photovoltaic device configuration. Along
with discussing these results, we would also be discussing the interplay of the three components of this ternary system to
both open circuit voltage (Voc) and Isc. Further optimization in structure and morphology of these devices can lead to significant performance enhancement.
We report here on properties of Metal-Semiconductor-Metal cells based on poly(3-octylthiophene), P3OT. The diodes were fabricated by spin-coating of poly (3-octylthiophene) on an indium-tin oxide coated glass substrate and an aluminum top contact was evaporated onto the film. The optical and electrical characteristics of the diodes were studied. A power efficiency of 10-4 was obtained at AM 1.5 conditions, while the power efficiency reached its maximum of 6% under illumination at 256 nm at an intensity of 2 (mu) W/cm2.