2 research outputs found
Ultrathin, Flexible Organic–Inorganic Hybrid Solar Cells Based on Silicon Nanowires and PEDOT:PSS
Recently,
free-standing, ultrathin, single-crystal silicon (c-Si)
membranes have attracted considerable attention as a suitable material
for low-cost, mechanically flexible electronics. In this paper, we
report a promising ultrathin, flexible, hybrid solar cell based on
silicon nanowire (SiNW) arrays and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)
(PEDOT:PSS). The free-standing, ultrathin c-Si membranes of different
thicknesses were produced by KOH etching of double-side-polished silicon
wafers for various etching times. The processed free-standing silicon
membranes were observed to be mechanically flexible, and in spite
of their relatively small thickness, the samples tolerated the different
steps of solar cell fabrication, including surface nanotexturization,
spin-casting, dielectric film deposition, and metallization. However,
in terms of the optical performance, ultrathin c-Si membranes suffer
from noticeable transmission losses, especially in the long-wavelength
region. We describe the experimental performance of a promising light-trapping
scheme in the aforementioned ultrathin c-Si membranes of thicknesses
as small as 5.7 μm employing front-surface random SiNW texturization
in combination with a back-surface distribution of silver (Ag) nanoparticles
(NPs). We report the enhancement of both the short-circuit current
density (<i>J</i><sub>SC</sub>) and the open-circuit voltage
(<i>V</i><sub>OC</sub>) that has been achieved in the described
devices. Such enhancement is attributable to the plasmonic backscattering
effect of the back-surface Ag NPs, which led to an overall 10% increase
in the power conversion efficiency (PCE) of the devices compared to
similar structures without Ag NPs. A PCE in excess of 6.62% has been
achieved in the described devices having a c-Si membrane of thickness
8.6 μm. The described device technology could prove crucial
in achieving an efficient, low-cost, mechanically flexible photovoltaic
device in the near future
Plasmonic Effects of Au/Ag Bimetallic Multispiked Nanoparticles for Photovoltaic Applications
In
recent years, there has been considerable interest in the use
of plasmons, that is, free electron oscillations in conductors, to
boost the performance of both organic and inorganic thin film solar
cells. This has been driven by the possibility of employing thin active
layers in solar cells in order to reduce materials costs, and is enabled
by significant advances in fabrication technology. The ability of
surface plasmons in metallic nanostructures to guide and confine light
in the nanometer scale has opened up new design possibilities for
solar cell devices. Here, we report the synthesis and characterization
of highly monodisperse, reasonably stable, multipode Au/Ag bimetallic
nanostructures using an inorganic additive as a ligand for photovoltaic
applications. A promising surface enhanced Raman scattering (SERS)
effect has been observed for the synthesized bimetallic Au/Ag multispiked
nanoparticles, which compare favorably well with their Au and Ag spherical
nanoparticle counterparts. The synthesized plasmonic nanostructures
were incorporated on the rear surface of an ultrathin planar c-silicon/organic
polymer hybrid solar cell, and the overall effect on photovoltaic
performance was investigated. A promising enhancement in solar cell
performance parameters, including both the open circuit voltage (<i>V</i><sub>OC</sub>) and short circuit current density (<i>J</i><sub>SC</sub>), has been observed by employing the aforementioned
bimetallic multispiked nanoparticles on the rear surface of solar
cell devices. A power conversion efficiency (PCE) value as high as
7.70% has been measured in a hybrid device with Au/Ag multispiked
nanoparticles on the rear surface of an ultrathin, crystalline silicon
(c-Si) membrane (∼12 μm). This value compares well to
the measured PCE value of 6.72% for a similar device without nanoparticles.
The experimental observations support the hope for a sizable PCE increase,
due to plasmon effects, in thin-film, c-Si solar cells in the near
future