Download Enhancement absorption of solar cells with plasmonic nanostructures

International Research Journal of Applied and Basic Sciences
© 2014 Available online at www.irjabs.com
ISSN 2251-838X / Vol, 8 (9): 1215-1221
Science Explorer Publications
Enhancement absorption of solar cells with
plasmonic nanostructures
Malihe Amiri, Tahmineh Jalali
Payame Noor University of Shiraz, Persian Gulf University of Bushehr
Corresponding author: Malihe amiri
ABSTRACT: In this paper, the increase of light absorption in thin-film solar cells is studied. In these cells,
light absorption becomes less due to reduced thickness. Light scattering by metallic nanoparticles is a
way to increase light absorption and depends on several factors. Here, two of the factors that one is
changing the distance between the nanoparticles and the next one is changing the nanoparticle type are
examined and the results are simulated by the finite element method (FEM). It is shown that by changing
the nanoparticle type and the periodicity of nanoparticles, the passing range can be increased.
Key words: solar cells, Plasmon nanostructure, absorption, pass
INTRODUCTION
Due to the increasing need of human energies and decreasing fossil fuel resources, the solar cells fossil
fuel is a viable alternative. The use of solar cells, while being healthy, is expensive and is mainly used in cases
such as satellites and spacecraft and also the optical calculators that have a very low voltage. For this reason, we
are looking for ways to reduce production costs. One of the ways is using the thin layer solar cells, but since the
light absorption is decreased by reducing the thickness of the cell and its efficiency becomes low, thus we need to
increase light absorption in these cells. Initial works by Stenzel and others were done on the improvement of optical
flow to 2/7 for indium - copper phthalocyanine structure (ITO) (Westphalen et al, 2000). Rand and others reported
a better performance of inorganic solar cells because of the thin film of silver nanoparticles (Rand et al, 2004).
Stuart and Hall showed that improving the flow of light can be done for a light detector at a wavelength of 165 nm
silicon with thickness of 800nm with the use of silver nanoparticles on the surface (Stuart and Hall, 1998). Shot and
others deposited the gold nanoparticles on solar cells and improved it to 80% at a wavelength of 500 nm. (Schaadt
and colleagues, 2005). A new method to enhance the absorption is the use of Plasmonic nanostructures. In this
method, the nano metallic structures are located at thin film solar cell structures. These structures enhance the light
trapping and create a large scattering cross-section and it increases the distribution of short-circuit current
density and thereby increases efficiency of thin layer solar cells (Ferry et al, 2010).
In this paper, using the finite element method through reflection spectra for thin-film solar cells are
simulated as Plasmonic. Plasmonic nanostructures are initially examined the finite element method is briefly
described and the final layout simulation, discussion and survey results and conclusions are presented.
Plasmonic nanostructures
If the frequency of light when light is shone on the surface of the plasma frequency of the conduction band
electrons of the same metal as the metal began to swing the swing they are said Plasmonic surface.
Plasmonicnanosolar cell structures can be used in three ways. Metal nanoparticles on the surface in this case,
when cells are subjected to high light shine login first nanoparticles to cells and then diffuse into the cell and the
cell it wants to light Nano particle
retention by taking out another, and then again in the cells is scattered. It also increased the absorption of
light when high Electrons and holes are generated also increases the cell efficiency increases. Alternatively, the
metal nanoparticles within the absorber can reflect by. In this case the nanoparticles are absorbed by concentrated
light increases. In this case, care must be taken to capture the nanoparticle layer should be less than is catchy and
the dorsal surface of the metallic nanoparticles can be reflected by the cell. In this case, the surface between the
metal and the catchy raised Plasmonic Light Square will refocus and increase uptake into cells ( Atwater and
Polman, 2010 - Green and Pillai, 2012 ). The size, shape and type of nanoparticles play an important role in the
Intl. Res. J. Appl. Basic. Sci. Vol., 8 (9), 1215-1221, 2014
scattering of light by them. If the particle diameter is smaller than the wavelength of light absorption and scattering
obtained from the following relations.
𝐶𝑠𝑐𝑎𝑡 =
𝐶𝑎𝑏𝑠 =
2𝜋 4
1
6𝜋
2𝜋
𝜆
𝛼
2
(1)
𝐼𝑚 𝛼
(2)
𝜆
𝜀 𝑝 𝜀 𝑚 −1
𝜀 𝑝 𝜀 𝑚 +2
𝛼 = 3𝑉
(3)
When𝜀𝑝 = −2𝜀𝑚 Plasmon surface resonance occurs at resonance, the particle scattering cross section is larger
than the geometrical cross section of it improves the optical flow (Bohren and Huffman, 1983 - Kreibig and Vollmer,
1995 - Mertns et al, 2007). If the disk is large, light scattering particles within the layer increases as the mass of
nano-shell, and also reduces the optical flow. For metals with the absorption band of low dielectric function is
derived from a model of peace.
𝜔
𝜀 =1− 2 𝑝
(4)
𝜔 +𝑖𝛾𝜔
Where 𝜔𝑝 is Plasma frequency.
𝜔𝑝2 =
𝑁𝑒 2
(5)
𝑚 𝜀0
By replacing 4 in 3 we have
𝜔 𝑝2
2
𝜔 𝑝 −3𝜔 2 −𝑖𝛾𝜔
𝛼 = 3𝑉
(6)
The resonance frequency of spherical nanoparticles surface Palsmon outdoors in occurs in 𝜔𝑠𝑝 = 3𝜔𝑝 and since
𝜔𝑝 Is dependent to the density of free electrons 𝜔𝑠𝑝 Will be dependent on electron density. Of nanoparticles, such
as gold, silver, aluminum, silver, aluminum, and more free electron density Have. The resonant frequency of the
built environment is dependent dielectric functions. Larger dielectric function leads to a frequency shift toward the
red wavelengths, So by changing the dielectric function can improve the optical flow (Xu et al, 2013 - Mertens et al,
2004 ).
Diffraction gratings
Nanoparticles into periodic gratings have assumed, for the width of a diffraction grating with N slots, each slot is b,
and a is gap between successive diffraction intensity is given by the following equation.
𝐼 = 𝐼0
𝛽=
𝑠𝑖𝑛𝛽 2
𝛽
𝜋𝑏
𝜆
𝜋𝑎
𝑠𝑖𝑛𝑁𝛼 2
(7)
𝑠𝑖𝑛𝛼
𝑠𝑖𝑛𝜃𝑛
(8)
𝛼=
𝑠𝑖𝑛𝜃𝑛
(9)
𝜆
Considering the two diffracted beams, the difference of the two beams is a multiple of the wavelength of the
maximum of the right intensity can be obtained by mesh relationship. (figure 1)
𝑎(𝑠𝑖𝑛𝜃𝑖 + 𝑠𝑖𝑛𝜃𝑛 ) = 𝑚𝜆𝑚 = 0, ±1
(10)
𝜃𝑖 is the angle of radiation,𝜃𝑛 is the angle of diffraction and m stands for diffraction order.
Figure 1 . View track-ray diffraction before and after
If the light is perpendicular to the grating (periodic gold nanoparticle) (𝜃𝑖 = 0 ) in this case, the light passes
through the perpendicular and no diffraction is not observed. The next maximum are formatedtow sides of zero
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Intl. Res. J. Appl. Basic. Sci. Vol., 8 (9), 1215-1221, 2014
point az 𝑚 = ±1. az you see on graph below 𝑇1 and 𝑇−1 and𝑇𝑜 also 𝑅1 and𝑅−1 and𝑅0 illustrated. az you see the
maximum level of diffraction for 𝑅−1 and 𝑇1 indicated.(figure 2)
Figure 2. Diagram of the transmitted and reflected diffraction
FINITE ELEMENT METHOD
Finite element method is a mathematical tool which physical devices are networked with smaller and
simpler form. In this way, wave equation at all points on the top and we calculate exist. In this case the number of
equations and unknowns. The governing equations and the finite element method are used by various applications
are resolved. Finite element method can be solved in two ways for electromagnetic problems. A range of methods the time at which the time-dependent Maxwell's equations are solved and another domain - that is coupled to the
two methods distribution and special value is divided. Trends for waves that are published in the open system and
method for scattering of waves in a closed system some special method we use. Governing equations must be
solved by applying the boundary conditions leads to the following matrix ourselves.
𝐴 𝑋 = 𝑏
𝑏 is column matrix that is indicated in accordance with boundary conditions and 𝐴 is a square matrix 𝑁 × 𝑁 that
usually is symmetrical.(Volakis et al, 1997)
Simulation Layout
To study the absorption and reflection of solar cell film Plasmonic, finite element method for simulating the periodic
array of Gold consider that the rotation distance between nanoparticles is within the simulated space (Figure 3).
Structure to consider the two-layer bottom layer of dielectric material of refractive index 1/2, and the top layer
refractive index of air is 1.
Figure 3 . Simulation of the finite element method for periodic arrays of gold nanoparticles
Port boundary condition imposed at the top and bottom of the boundary conditions have led to an incoming
wave is completely absorbed and do not have any reflection and the right side has the periodic boundary
conditions. Nanoparticles that are periodically meet this requirement. Gold nanoparticles into the cell has the profile
for both TM and TE modes is observed in (Figure 4).
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Figure 4. Profile field radiated by a flat wave A)TM modefor B)TE mode
RESULTS AND DISCUSSION
Finite element method, in order to increase the efficiency of thin film solar cells Plasmonic, two parameters
of nanoparticles and nanoparticles studied period process. Depending on the angle of reflection and transmission
diagram (Figure 5) for both TM and TE modes are shown for gold nanoparticles. 𝑅0 reflection coefficient for Mode
TE( Figure 5– B) fairly smoothly with increasing angle increases. 𝑇0 coefficient with increasing angle decreases.
Here are the Index 0 and ±1 orders of diffraction .
A )Mode TM
B)Mode TE
Figure 5. Diagram of reflection( R)and pass( T)for thin-film solar cells with gold nanoparticles A) TM mode
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B) TE mode
The diagram TM and TE reflection of light at different angles in the eighty degrees to its maximum value
and the resulting spectrum is the lowest level crossing. In (Figure 6) the period between the nanoparticles has to
change and change 380,450, 420,400 and500, per different angles taken into account, we see the passing
spectrum decreases with increasing period of nanoparticle so that the maximum of passing spectrum is due to 380
nm period and the minimum 0f passing spectrum is due to 500 nm period. Because increasing the period of
nanoparticles is weakened. In all curves, as well as increasing the range of approximately password angle of 80
degrees to decrease and reaches it’s minimum.
Figure 6. Spectrum passwords for different rotation periods for the Model TM
In (Figure 7) passes to wide variety of nanoparticles, including gold, silver and aluminum are discussed.
Observe greater range of silver and aluminum cross more silver than gold because silver and aluminum than the
free electron density and intensification Plasmonic gold surface in the ultraviolet region is created - Be reflected in
the ultraviolet region of the spectrum decreases more passes. And aluminum tape to reflect the reduced absorption
Thus, the cross-spectrum of silver increases. And what about gold because its surface Plasmonic resonance
occurs in the visible region, the spectrum of the reduced cross.
Figure 7 . pass range for various nanoparticles for Mode TM
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Figure 8 . Reflection for various nanoparticles for Mode TM
According to the transmission and reflection charts, graphs, which capture the equation 𝐴𝑏𝑠𝑜𝑟𝑝𝑡𝑖𝑜𝑛 = 1 − 𝑇 − 𝑅
Calculated as follows obtains.( Figure 9 )As can be seen in Figure attracts more gold than silver, more silver
absorption of aluminum.
Figure 9 . adsorption of nanoparticles for Mode TM
CONCLUSION
In this paper, we have studied solar cells Plasmonic. Finite element modeling is performed using these
cells. In order to increase the absorption Film solar cells, metal nanoparticles have been used as sex and period
nanoparticles have changed. According to the Light trapping in metallic nanoparticles depend on their dielectric
functions, is shown by placing the nanoparticle uptake into cells, resulting in Interest increases. Aluminum, silver
and gold also has a range of more than passing. As a result, the spectrum of light increases the period between
because nanoparticles decrease with increasing periodicity is weaker field.
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