Session C12
#200
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NANOCATALYTIC WET-CHEMICAL ETCHING AND THE FUTURE OF
SOLAR CELL TECHNOLOGY
Kai Gentile-Manigault ([email protected], Sanchez 5:00), Colin O’Dowd ([email protected], Mena 1:00)
Abstract—Our paper analyzes black silicon nanocatalytic
wet-chemical etching using nanoparticles, which yields
more economic and efficient solar cells. It discusses
current problems including silicon, used in most cells,
having relatively low rates of absorbance and conversion
from light to electricity [3]. The National Renewable
Energy Laboratory(NREL) has improved this by creating
a liquid that etches nanoscale pores into silicon wafers and
then filling the pores with gold particles. [3]. We describe
how the etched nanoscale voids reduce reflectance [4]. The
result of the catalytic etching is a silicon wafer that
appears “black” to better absorb light energy, which
results in a record efficiency rate and reduction in costper-watt [5]. We will discuss how the societal impact will
be more competitive solar energy against fossil fuels which
will cause countries to move away from hazardous fossil
fuels. We begin with discussion of conventional solar cells
and an explanation of their functioning. Next, we will
explain how this technology improves upon conventional
solar cells and how they will increase competitiveness
against fossil fuels to allow for energy production that is
ethical and efficient. Lastly, we will further discuss the
inverse trend between solar energy production and
projected costs of these etched cells and future applications
of this nanoparticle etching process.
Key Words—Black silicon, etching,
semiconductor, nanotechnology.
solar
cell,
THE STRUGGLE TOWARDS SOLAR
ENERGY
Many countries today are trying to move away from
dependence on fossil fuels and focus on more renewable
energy sources, one of the most famous being energy from
solar panels. The use of solar panels to convert sunlight into
electrical energy has several benefits such as low emissions
and renewability. However, solar energy constitutes only
about 1% of the world’s energy due to high cost of
producing solar cells and efficiency problems, both
boundaries toward wide-spread implementation [1].
However, a technique called black silicon nanocatalytic
wet-chemical etching, developed through nanoparticle use,
University of Pittsburgh Swanson School of Engineering
Submission Date 31.03.2017
has the potential to yield more economic and efficient solar
cells. This process works by improving the performance of
solar cells by increasing the amount of light they absorb.
The cells essentially become “blacker” as they absorb more
light and reflect less. Knowing how this relates to the
chemical etching process and its potential impact on the
energy industry first takes an understanding of how
conventional solar cells today are built and what they do.
FUNCTION OF SOLAR CELLS
Solar cells, also called photovoltaic cells, turn energy
from light into electrical energy. Though many different
types of solar cells have been created since the late 20th
century, they all rely on the same basic principal: the
photovoltaic effect. The process begins at the sun, Earth’s
most sustainable energy source. The Sun radiates energy as
light through tiny particles called photons. Photons are the
particles that carry force in electromagnetic waves. The
photons from the sun transfer energy to the earth through
light and heat. All energy on earth comes from the Sun. In
fact, the sun “provides enough energy in one minute to
supply the world's energy needs for one year” [6]. This
sustained bombardment of energy-rich particles is the
largest, and least used source of energy available to us on
Earth. Solar cells harness this energy through the
photovoltaic effect. This is when the high-energy photons
strike a surface, transferring its energy to the electrons on
the surface, which excites the electrons into a higher energy
state. Photovoltaic cells are made up of semiconductors, in
this case called photo conductors, which take advantage of
the photovoltaic effect to “change their conductivity when
struck by light” [10]. This is caused by the high-energy
electrons that become free in the semiconductor when they
reach a high-energy state. Each free electron is part of an
electron hole pair that will separate into opposite charges.
The electron hole is the space where the electron should
have been on the atoms of the semiconductor [11]. The
electron and its hole are pushed in separate directions by an
electric field. As they move apart, they form a difference in
electric potential, also known as voltage, that creates an
electric current in the direction opposite that of the
Kai Gentile-Manigault
Colin O’Dowd
electrons
to
produce
accessible
electricity
[10].
are then put into panels, or used individually to power small
devices. Monocrystalline panels are made up of a thin slice
of monocrystalline silicon cells encased in protective EVA
(ethylene vinyl acetate), this protects the photovoltaic from
contamination, which is then enclosed with a glass top to
let in sunlight and a protective film backing that aids in the
absorption of light [6]. Under direct sunlight, solar cells are
a clean, sustainable source of renewable energy. Though
these cells can turn light from the sun into useable
electricity, they are still relatively inefficient, which will be
analyzed in the next section.
PROBLEMS WITH CONVENTIONAL SOLAR
CELLS
One of the biggest challenges solar energy faces is
efficiency. Efficiency in solar cells is the percent of energy
in photons that the photovoltaic cell can convert into
useable electrical energy. Many factors affect solar
efficiency, the most important being thermodynamic
efficiency, ultimate efficiency, quantum efficiency and
reflectivity.
Thermodynamic efficiency is affected
by the difference in energy of the sun’s photons and the
thermal energy of the cell itself. The thermodynamic
efficiency is also affected by the amount of sunlight that is
available to contact the cell [10]. Ultimate efficiency is the
solar cell’s ability to absorb the energy from photons to
create electron-hole pairs. Every semiconducting material
has its own band gap, a minimum and maximum energy
level where it can absorb the maximum energy [11].
Photons with energy below the band gap will not be
absorbed, and their energy will be released as heat, which
in turn decreases the thermodynamic efficiency by raising
the cell’s temperature and lowering the difference in
energy between the photons and the cell. Photons with
energy levels above the band gap will still be absorbed.
However, the excess energy will still be turned into heat,
lowering the thermodynamic efficiency [11]. Quantum
efficiency is the number of electron-hole pairs that become
useable current. Once the energy from the photons causes
an electron-hole pair, they could either separate to opposite
sides, which generates a current; or, they could recombine
and no current is generated [11]. Reflectivity also
contributes to the efficiency of solar cells. Since solar cells
rely on light as an energy source, any light that is reflected
is energy that won’t generate current. Reflection depends
on many things such as the coating used to seal the cells as
well as the angle at which light contacts the cells. Trying
to increase efficiency of solar cells tends to lead to
increased cost. Higher efficiency cells typically contain
more layers and therefore have a higher manufacturing
cost. Others rely on expensive elements such as platinum
FIGURE 1 [6] DEMONSTRATION OF
PHOTOVOLTIC EFFECT IN SOLAR CELLS
The above figure demonstrates the photovoltaic
effect in action, depicting where the voltage is transferred
throughout the cell and how the sunlight moves the
electrons creating electricity. Though all solar cells use this
same basic process, different types of cells have different
physical properties and designs which all differ slightly in
function and efficiency. Today, the most prevalent or
‘normal’ cells with the highest efficiency and longest
lifespan are monocrystalline silicon cells. Monocrystalline
silicon is an excellent semiconductor because of its purity
and crystal shape. The silicon crystals in monocrystalline
cells are continuous throughout the sheet, which allows for
better separation and flow of the electrons and their holes
[6]. The layers of silicon are doped with other molecules to
further aid the separation process.
In monocrystalline cells, there are two layers, one
n-type and one p-type. N-type semiconductors are doped
with atoms with five valence electrons which will
contribute extra electrons for the photovoltaic separation
[12]. On the other hand, p-type semiconductors are doped
with atoms that hold 3 valence electrons, producing holes,
“electron deficiency” [12]. The n-type and p-type layers
are sandwiched by contact sheets that conduct the current
as the electrons and holes separate [6]. Pairs of n and p
layers can be stacked to create Multijunction Cells that
absorb a larger portion of the visible light spectrum [6]. The
tops of the solar cells are layered with an antireflective
coating that keeps sunlight from being deflected, allowing
more photons to undergo the photovoltaic effect [6]. Cells
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Kai Gentile-Manigault
Colin O’Dowd
which greatly increase cost [6]. High quality silicon is a
large contributor to the cost of prevalent solar cells. More
pure silicon is expensive to manufacture, but leads to
higher cell efficiency. Most solar cells face this tradeoff,
cheaper cells are less efficient so electricity is more
expensive, but expensive, efficient cells make electricity
cheaper. A solar cell that can do both would not change the
industry but would have a notable impact on energy.
be reflected away from the cell on the surface [4]. The
trillions of holes that are created are also drilled to a variety
of different random lengths, which also increases how
gradually the light experiences the refractive change from
air to silicon [3]. These aspects of the cell etching provide
the cells with significant advantages over conventional
solar cells and etching techniques.
IMPROVEMENTS OVER
CONVENTIONAL SOLAR CELLS
AN INTRODUCTION TO
NANOCATALYTIC WET-CHEMICAL
ETCHING
Wet-chemically etched black silicon cells provide
several improvements over traditional solar cells. AS stated
earlier, the biggest problems most solar cells have faced
over the years are low efficiency rates and high cost per
wat of power. These will be major barriers to solar energy
being implemented on a large scale if they are not
minimized. According to the Nanotechnology Initiative,
“Today, the levelized cost of energy generated by solar
technology is not yet economically competitive with
conventional fossil fuel technologies without subsidies.
Therefore,
new
innovations
and
fundamental
breakthroughs can help accelerate the development of
economical solar energy technologies that surpass the
limits of existing technologies” which demonstrates the
main dilemma with solar cell implementation [2]. The
power they produce is often too costly compared to how
much the cells cost. The best way to improve efficiency is
to increase the amount of light that the cells absorb and
reduce how much they reflect. As stated earlier measures
have been taken to reduce reflectance such as covering the
cells with an anti-reflective coating and similar etching
process such as the metal-assisted etching described
earlier. But while these coatings do increase absorption
they do so at a higher cost [11]. The goal is to decrease and
reflectance and cost to yield a lower cost per wattage of
power. Black solar cell etching provides a solution to this
problem. The reason these cells show promise is due to the
etched “blackness” of the silicon wafer which increases
light absorbance, as seen below.
The importance behind nanocatalytic wet-chemical
etching is the effect it has on traditional silicon wafers,
particularly in regards to the textures. The etching process
conducted by the NREL involves spraying the surface of
silicon wafers with a low-cost nanoscale etching liquid.
The liquid creates gold nanoparticles on the surface of the
silicon which immediately begin to drill nanoscale holes
into the silicon [3]. The result is a silicon wafer etched with
tiny nanoscale cylindrical pores that appears “black” to
reduce reflectance and increase light absorption, as shown
below here.
FIGURE 2 [5] PICTURE OF BLACK SILICON
ETCHED CELL
Blackness is used to describe the color of the silicon and
how well the silicon absorbs light due to black objects
absorbing all spectra of visible light. The process is also
very quick, with a completion time of no more than three
minutes at room temperature [5]. The pores alter the depth
of the material as well as it’s refractive index which
accounts for why the pores reduce reflectance. Light is
reflected when it encounters a surface of considerably
different refractive index, which is the amount that a
material will bend light by. A “sharp interface” is an area
where a sudden considerable change in refractive index
occurs. However, the change in depth and refractive index
through the cell caused by the etching causes the refractive
index to change so gradually that light will not be reflected
once it goes from the air to the wafer and through the pores
[3]. The diameter of the pores is smaller than the
wavelength of light, about 500 nanometers, so light does
not encounter any “sharp interface” that would cause it to
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Kai Gentile-Manigault
Colin O’Dowd
research of black silicon wet-chemical etching at the
NREL, “Our thinking was if the goal is to make it cheaper,
we want to avoid using vacuum deposition completely”,
which demonstrates how this method of using low-cost
chemicals is currently the most cost-efficient way of
lowering cost and increasing efficiency [4].
The NREL’s method of wet-chemical etching is
different in that the silicon is directly sprayed with a liquid
called chloroauric acid that creates gold nanoparticles on
the surface instead of nanoparticles being put on with a
vacuum. This is what makes this process much cheaper
than the conventional way of drilling holes into the silicon.
The conventional way uses colloidal gold nanoparticles
that are placed on the silicon, while chloroauric acid is less
expensive and easier to put on than colloidal gold particles
[4]. Also, according to Branz, “Our method gives a blacker
silicon and would replace an expensive vacuum deposition
system with a single, cheap, wet etch step” with the term
“blacker” meaning a more etched silicon wafer [4]. The
more etching a silicon wafer has, the greater it’s light
absorbance, so in essence this method not only save time
and money but creates a more efficient solar cell. A bonus
of using this method is its better absorbance at different
times of the day. The absorbance of solar cells varies
throughout the day due to the angle that the solar cells are
receiving light as the Earth rotates around the sun. Because
of this, absorbance is lowest and reflection highest in the
early mornings and afternoons due to the angle. However,
the black silicon created by the wet-chemical etching
process better prevents low-angle light reflection than
other solar cells [5]. The etched cells have the potential to
increase energy output by 1% to 3% due to thier superior
angle of incidence performance [3]. The combined benefits
of the wet-chemically etched black cells allow it to reduce
the cost of each photo-voltaic array by 2.5% [3]. Greater
cell efficiency is not the only way the wet-chemical etching
increases amount of power per cost of each cell. The
etching process also increases this ratio by directly
lowering the cost to make each cell.
Wet-chemical etching reduces solar cell
manufacturing costs. According to Al Goodrich, senior
cost analyst for NREL's PV manufacturing division, the
wet-chemical etching process “…requires about a third less
energy than adding the conventional anti-reflection layer to
the finished solar cell” [5]. In addition, the wet-chemical
etching process saves money by eliminating the use of
vacuum tools used in conventional etching to put the
colloidal gold on the silicon cells [4]. Goodrich states that
it cuts factory production costs by about %10. This greater
increases the cost-per watt because overall manufacturing
costs are lower, which means a higher watt per cost ratio
FIGURE 2 [6] GRAPH COMPARING
LIGHT ABSORBTION OF ETCHED VS. NONETCHED SILICON
The figure demonstrates how black silicon absorbs a
broader spectrum of light than conventional solar cells,
with the most wavelengths being absorbed by the black
layer. The NREL’s experiments resulted in the solar cells
having an impressive 16.2% efficiency rate, whereas
conventional solar cells without anti-reflective coatings
have not exceeded 13.9% [5]. The etching process has the
potential to boost light absorbance from the standard 93%
to 95% of most solar cells to 98%, a 3% to 5% increase [9].
This increase in efficiency will save an estimated $.021 to
$.028 per watt, a 16% reduction in cost per watt [5]. In
terms of panels, this would mean a $4 to $8 reduction in
cost-per 200 watt panel [3].
Although the results of this process are
impressive, this is not the first that the world has seen of
etching nanoscale pores into silicon to increase absorbance.
There have been other methods used to produce nanoscale
pores in solar cells such as using lasers and reactive ion
etching [8]. However, the most commonly used chemically
based process is metal-assisted etching, which was first
performed in 2006 at the Technical University of Munich
[4]. The process is typically performed by first covering the
silicon in a sheet of metal nanoparticles, normally gold or
silver, using a vacuum and then submerging the silicon in
a solution containing hydrofluoric acid and an oxidizing
agent such as hydrogen peroxide [9]. The metal
nanoparticles obtained valence electrons from the silicon
surface which causes them to become ions that drill holes
into the silicon surface [9]. The area in the holes contain
silicon oxidized by the oxidizing agent in the solution but
are removed by the hydrofluoric acid, creating pores [9].
After this, the silicon is taken out of the hydrofluoric acid
and the metal particles are removed, after which the silicon
is cleaned [9]. According to Howard Branz, head of
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Kai Gentile-Manigault
Colin O’Dowd
and, thus, more economically competitive solar cells [4].
Another improvement of wet-chemical etching
has over conventional cells is how it decreases the effect of
solar cell manufacturing on the environment. Although the
goal is to improve solar cell efficiency to encourage wider
implementation of solar cells that will help the
environment, this wet-chemical etching process also helps
the environment in a more direct manner. According the
NREL, the wet-chemical etching process replaces another
commonly used process in etching solar cells that involves
using saline gas as well as many of the chemicals used for
cleaning in the process mentioned earlier [4]. These
chemicals are 17000 times more dangerous than carbon
dioxide in regards to greenhouse gas emissions and
increasing global warming [4]. Reducing usage of these
chemicals aids in preventing more air pollution. There are
numerous benefits of etching cells with this technique, but
the measure of how useful this etching technique will be
being how and what applications may come from using it.
power for the lifetime of the solar cells, which could be
twenty to thirty years [14]. The possibilities with efficient
solar energy are endless. Any field or rooftop with strong,
persistent sunlight could turn into a possible source of
useable electricity. Personal, home based solar cells could
me a major application of black silicon solar cells. With
cheap, high efficiency cells, it could be possible to run
homes effectively and comfortably completely off their
own solar power. If so many people catch on that selfsustaining homes become the norm, the world could enter
a new era of efficient, sustainable energy. A revolution of
this sort would surely put solar as the leading source of
clean, efficient power.
As mentioned earlier, the texture of black silicon
cells allows them to absorb the sun’s rays from lower
angles meaning home based solar systems could be viable
for homes at greater latitudes than previously thought.
Applications for black silicon cells extend past the reaches
of earth’s atmosphere. Solar panels are used to power
satellites could soon be switched to more efficient versions.
This will give satellites access to more power and could
boost their lifetime. Efficient solar could vastly extend the
range and lifetime of space probes and could power the
next generation of space exploration. Black silicon and
nanocatalytic
wet-chemical
etching
are
great
improvements to solar and come with many applications
and a promising future. Innovation like this will eventually
make solar a top energy contributor with a strong future of
numerous applications. The numerous benefits and
applications of these wet-etched black silicon cells are
clear to see, but what is even more impressive is the steps
that this new etching process will allow us to take towards
a more sustainable and ethically considerate society.
SOLAR CELL APPLICATIONS
The increased efficiency that nanocatalytic wetchemical etching brings to solar cells gives them a wide
variety of applications. The greatest applications range
from large scale solar farms to small, residential
installments, to space based systems outside of the Earth’s
atmosphere. Large, utility scale solar power plants will
benefit heavily from the higher efficiency of newer solar
cells. The reduced cost will allow for larger facilities to
prevail and become more profitable. The increased
absorbance spectrum from the chemical etching will allow
large scale solar power plants to be put at higher latitudes
where the sun’s rays would normally reflect from older
solar panels [6]. Vast solar power stations in ideal
locations, like the American southwest could emerge as a
dominant contributor of electricity. Another utility scale
application is implementation of nanocatalytic wetchemically etched cells on concentrated photovoltaic
systems. These systems use mirrors to concentrate sunlight
onto high efficiency solar cells [6]. Systems such as this are
becoming increasingly popular with medium to large
companies trying to cut back on utility bills. Fairly large
solar systems can be placed on the rooftops of large
factories and warehouses [14]. Cheaper solar is a great
opportunity and many companies are taking advantage. In
fact, “Solar Means Business report show that major U.S.
corporations, including Target, Walmart and Apple are
going solar at an incredible rate” [14]. Because solar panels
don’t have much cost after the initial purchase and
installation, companies with enough capital to purchase
large quantities of solar cells will have clean, reliable
IMPACT ON ENERGY
Major breakthroughs in solar energy such as
nanocatalytic wetchemical etching are creating a promising
future for solar energy and could have a major impact on
the place of solar energy in the energy industry. As solar
energy continues to become cheaper and more efficient, it
gains a financial foothold against nonrenewable energy
sources. The high cost of solar energy has been holding
back its full potential. As processes like nanocatalytic wetchemical etching continue to drive the price of solar energy
down, showing investors its sustainability and profitability,
the incentive to switch from nonrenewable sources rises.
Eventually, a point will be reached where solar energy and
nonrenewable energy are equal in cost. This is where solar
will begin to triumph. Once cost will no longer be a factor,
solar will surpass nonrenewable sources because of its
lower environmental effects. Experts have projected that
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Kai Gentile-Manigault
Colin O’Dowd
solar could be cost competitive as early as ten years if it
continues to grow in the same way it is now [13]. If this
projection is true, it will lead to an exponential increase in
solar energy use and solar energy’s as a sustainable part in
the world economy. This will factor greatly into the growth
of solar energy. Once investors can see solar as highly
profitable, solar will become a staple on the economy. This
will cause a flood of new capital for research and solar
production, which in theory would lower costs even
further. According to the Solar Energy Industries
Association, there are already 209,000 jobs in solar in the
United States alone [14]. They also project this number to
increase to 360,000 American jobs by the year 2021. This
does not even consider the possible jobs solar could bring
to other parts of the world. Any region on earth with clear,
daily, direct sunlight has the potential to harness all the
power, literally and figuratively, that innovations in solar
will offer. The American southwest has a lot of potential
for vast solar installations. California has already taken
advantage of the solar boom by installing implementing
enough solar to make up 34% of the total solar power in
the United States [14]. Improvements in solar and cost
reductions will also pave the way for more homeowners
taking advantage of solar. Not only will the costs of home
systems drop, but also the increased efficiency will allow
for greater power generation which saves the homeowners
more money overall, effectively raising the incentive to
switch to solar even higher. Nanocatalytic wet-chemical
etching is just one of many innovations contributing to the
booming solar energy industry. Its impact has the
possibility to revolutionize the energy industry for cleaner,
cheaper, more efficient power generation. The end goal is
to lower the cost of solar so it is so inexpensive that it
would be detrimental to use anything but solar. If solar
technology were to reach this point, it would open a door
to numerous solar cell applications. Nanocatalytic wetchemical etching, a method of solar cell improvement
developed by the NREL, may just allow us to accomplish
this. What it is and its importance will be will be explained
in the next section.
technology because it crucial for it to be in the best interest
of all parts of society in order to benefit everyone in it.
Technology that puts economically depressed areas at risk,
cause harm to the environment, or cause health concerns
may improve parts of society but do not contribute to it’s
overall growth due to the trade offs involved with it. Black
silicon solar cells benefit everybody in that they are
cheaper than usual cell, produce no waste and do not cause
any potential harm to citizens. This is the reason for its
implementation. This would also reduce the dependence of
many cities and nations on fossil fuels, which are not
sustainable. Fossil fuels are cheap but pollute the
environment and put public health at risk. Replacement of
fossil fuels with solar energy increases the efficiency as
well as ethical standards of society because it takes away
the trade-off between a cheap and reliable source of energy
with the many environmental and even health
consequences associated with it. Solar energy is one of the
most sustainable, yet underused sources of clean renewable
energy. Increased solar usage would cut down on adverse
environmental effects of many nonrenewable energy
sources as well as toxic waste in landfills. Because Solar
panels are highly recyclable, old solar panels will just be
processed and made into new, more efficient ones in the
future. This is highly sustainable because new panels will
need less new natural resources than old panels. Solar
energy will be very important to environmental
sustainability and stability. Carbon dioxide emissions from
burning carbon dioxide penetrate the Earth’s atmosphere
and cause a phenomenon called “global warming”. This
occurs by the emissions trapping the radiation from the sun
that would have been reflected back into space by the
Earth’s surface with the Earth’s atmosphere. This excess
heat causes the surface temperature of the Earth to increase.
Significant climate change such as glaciers melting,
causing sea levels to rise, and loss of habitats and
ecosystems has been linked to the increase in pollution by
humans.
Solar energy helps us sustain the current standard
of living humans enjoy on Earth without being detrimental
to the millions of other species we share it with. Pollution
from burning fossil fuels also has adverse health effects.
According to the World Health Organization, there are
over 7 million premature deaths linked to air pollution [15].
The types of diseases caused by air pollution include, but
are not limited to, respiratory and pulmonary diseases as
well as cancer [15]. An area that particularly suffers from
this relationship between air pollution and disease are low
and middle-income areas in South East Asian regions,
where an estimated 2.2 million deaths had been recorded in
2012 [15]. According to Dr. Flavia Bustreo, World Health
ETHICAL CONSIDERATIONS AND
SUSTAINABILITY
The goal of black silicon etched cells is to advance the
most sustainable means of energy production known today.
What it means for something to be sustainable is for it to
beneficial from all facets of society. This means that the
technology is not only environmentally friendly but also
does not cause economic troubles with it’s cost and cause
societal problems such as health concerns. Sustainability is
the most important aspect of any brand new piece of
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Colin O’Dowd
Organization Assistant Director-General Family, Women
and Children’s Health, “Cleaning up the air we breathe
prevents noncommunicable diseases as well as reduces
disease risks among women and vulnerable groups,
including children and the elderly”, therefore preventing
air pollution is imperative for protecting these vulnerable
groups of people [15]. The amount of people and land
affected by air pollution is staggering, and only increases
with Earth’s growing population and industrialization.
However, greater implementation of solar energy would
help lower these numbers. Therefore, it is not only in the
interest of economically and efficiently producing energy
that solar cell usage should be expanded, but also the
ethical responsibility of every nation as they would reduce
the risk of millions of air-pollution related deaths
worldwide. The barrier to this does not particularly come
from nations not wanting to turn to clean sources of energy,
but comes from the costs of generating power from solar
cells as well as other means of renewable energy such as
wind and geothermal sources. In the past, high cost has left
it economically unsustainable because the lower profit
drives away potential investors. Nanocatalytic wetchemical etching has the potential to make solar cell usage
an ethically advantageous choice to produce energy as well
as an economically advantageous one due to it reducing the
amount of cost per watt of power. As this chemical etching
process is improved upon to greater reduce the reflectance
of light and increase absorption for greater power output,
societies around the world will see this technology as
advantageous in the short and long term. As stated by
NREL Vice President for Commercialization &
Technology Transfer William Farris, “This technology will
play an important role in moving forward the availability
of solar technologies” [7]. Implementing the technology
will be initially advantageous because it’s cost per watt will
be competitive with that of fossil fuels, and better in the
long term because it will reduce deaths and millions of
dollars in healthcare expenditures and environmental
conservation efforts. This wet-chemical etching process
will greatly expand the influence of solar power reducing
millions of tons of emission while saving millions of lives
and acres of nature at the same time.
energy, including high cost and low yield of energy, will
be minimized more and more as this technique is improved
upon and, ultimately, becomes the most efficient and
cheapest etching process known today. The demand for a
clean and renewable source of energy increases everyday
as more of the Earth’s resources are depleted and more of
the environment and population of the Earth are adversely
affected by the waste and extraction procedures associated
with fossil fuels. When the wet-chemical etching process
becomes improved to the point in which the cost of power
from solar cells becomes similar to that of fossil fuels, it is
very likely that we will see a large trend toward solar
energy due to its substantial benefits over fossil fuels,
including no waste and pollution and abundant supply.
Funding research into this process of solar cell
improvement will be a major step toward obtaining an
economically, environmentally, and socially sustainable
world.
SOURCES
[1] Energy Post. “Solar Power Passes 1% Global
Threshold” Energy Post. 6.11.2015. Accessed 1.09.2017
http://energypost.eu/solar-power-passes-1-globalthreshold/
[2] “NSI: Nanotechnology for Solar Energy Collection and
Conversion—Contributing to Energy Solutions for the
Future” National Nanotechnology Initiative. Accessed
1.10.2017 http://www.nano.gov/node/830
[3] “NREL’s Black Silicon Increases Solar Cell Efficiency
by Reducing Reflected Sunlight” National Renewable
Energy
Laboratory.
Accessed
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CONCLUSION: SOLAR ENERGY AS A
STEP TOWARD A SUSTAINABLE
FUTURE
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Nanocatalytic wet-chemical etching is a technique that
has the potential to revolutionize solar energy. The promise
that this technique provides is that solar energy will finally
be competitive against cheap, hazardous fossil fuels. The
boundaries toward wide spread implementation of solar
7
Kai Gentile-Manigault
Colin O’Dowd
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ACKNOWLEDGEMENTS
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We would like to acknowledge Michelle for
advising us to discuss ethics in our paper and Dr. Budny
for giving us the idea to merge our topics.
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ADDITIONAL SOURCES
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8