NAN O E X P R E S S Open Access
Improved photovoltaic performance of silicon
nanowire/organic hybrid solar cells by
incorporating silver nanoparticles
Kong Liu
1
, Shengchun Qu
1*
, Xinhui Zhang
2
, Furui Tan
1
and Zhanguo Wang
1
Abstract
Silicon nanowire (SiNW) arrays show an excellent light-trapping characteristic and high mobility for carriers. Surface
plasmon resonance of silver nanoparticles (AgNPs) can be used to increase light scattering and absorption in solar
cells. We fabricated a new kind of SiNW/organic hybrid solar cell by introducing AgNPs. Reflection spectra confirm
the improved light scattering of AgNP-decorated SiNW arrays. A double-junction tandem structure was designed to
manufacture our hybrid cells. Both short-circuit current and external quantum efficiency measurements show an
enhancement in optical absorption of organic layer, especially at lower wavelengths.
Keywords: Silicon nanowire, Silver nanoparticle, Surface plasmon resonance, Hybrid solar cell
Background
Organic solar cells have emerged as potential energy
conversion devices for several advantages, including
flexibility, lightweight, semi-transparent characteristics,
and ability to large-scale production at low temperature
[1-3]. However, their reported efficiencies are still very
low even for laboratory cells. The most crucial problems
many of these devices face are limited mobility of charge
carriers and rapid recombination. To mitigate these
problems, some special methods, such as reducing the
thickness of the active layer of solar cell and incorporat-
ing inorganic materials with high carrier mobility, have
been taken for effective charge separation [4-6].
One of these inorganic materials is silicon nanowires
(SiNWs) [7-9]. Most recently, some research groups
have demonstrated fabrication of SiNW/organic hybrid
solar cells [10-16]. These SiNWs can offer at least three
advantages for solar energy conversion. First, they pro-
vide high-mobility pathway from the active interface to
the electrodes for carriers. Second, they can significantly
reduce reflection and induce strong light trapping between
nanowires, resulting in strong absorption. Finally, they in-
crease the contact area between the two materials.
On the other hand, application of AgNPs in organic
photovoltaic devices is of considerable interest [17]. Sur-
face plasmon resonance in AgNPs offers a promising
way to enhance the power conversion efficiency (PCE)
of organic solar cells as it exhibits strong local field en-
hancement around the AgNPs, which can increase light
scattering and absorption in the organic film [18-21]. In
recent years, a simple method for depositing AgNPs on
silicon wafers by galvanic displacement has received
renewed interests [22 ]. As a versatile fabrication method,
it is well suited to yield films with high purity and sub-
strate adhesion [23]. Thus, it is expected that the inte-
gration of AgNP-decorated SiNW array and polymer
could lead to a simple process and high-performance
solar cells.
In this work, we report an efficient approach for
enhancing the PCE of SiNW/poly(3-hexylthiophene)
(P3HT):[6]-phenyl-C61-butyric acid methyl ester
(PCBM) hybrid solar cells by decorating AgNPs on the
SiNW surface. In order to evaluate the performance of
the scattering effect of AgNPs, we have prepared differ-
ent diameters of AgNP-decorated SiNW array samples
by vary ing Ag deposition duration, with a Ag-free SiNW
array sample as reference. Some hybrid solar cells with
the structure of Al/n-type SiNW/AgNP/P3HT:PCBM/
* Correspondence: qsc@semi.ac.cn
1
Key Laboratory of Semiconductor Materials Science, Institute of
Semiconductor, Chinese Academy of Sciences, Beijing 100083, People's
Republic of China
Full list of author information is available at the end of the article
© 2013 Liu et al.; licensee Springer. This is an Open Access article distributed under the terms of the Creative Commons
Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction
in any medium, provided the original work is properly cited.
Liu et al. Nanoscale Research Letters 2013, 8:88
http://www.nanoscalereslett.com/content/8/1/88