Running Head: Photosynthesis and Semi-Conductor based Solar Cells

Photosynthesis and Semi-Conductor based Solar Cells

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October 22, 2011

Photosynthesis and Semi-Conductor based Solar Cells

Plants opened opportunities to develop a source of energy from the photosynthesis process. Experts have tried to reproduce the process of photosynthesis with unproductive outcomes. For the purpose of this assignment, will explore energy generated processes through photosynthesis and a semi-conductor based solar cell. Also, will explain how both processes are related to the laws of thermodynamics.

Both processes have similarities, and differences. Amid the similitude's are that both processes gather sunlight, separate water molecules, and generate energy outputs. For instance, plants receive sunlight when are on direct contact with the sun, while solar cells collect rays through photovoltaic (PV) panels. Sunlight energy is immersed when "large numbers of chlorophyll molecules acts as the antenna that actually harvest sunlight and start to convert it in to a useful form"(Why are plants green? - MSU Physics and Astronomy, 1996). Both photosynthesis and semi-conductor based solar cells are significant due to their possibilities of production. “Photosynthesis is the process by which plants, use the energy from sunlight to produce sugar, which cellular respiration converts into ATP, the "fuel" used by all living things. The conversion of unusable sunlight energy into usable chemical energy, is associated with the actions of the green pigment chlorophyll”(PHOTOSYNTHESIS - Maricopa Community Colleges, 2010).

Throughout the photosynthesis process plants add in solar energy, and carbon dioxide to change water molecules into hydrogen, electrons, and oxygen. Generating electricity by means of solar cells is quite similar to the light reaction of photosynthesis. “This process is called photovoltaics. The electrons in the solar cell capture light energy and are boosted to a high energy level where they are accepted by the wire making up the electrical circuit” (photovoltaics and photosynthesis, 2001). Both processes cause the lost of electrons. In the case of the solar panels, the lost of electrons occurs when protons within the sun rays hit the solar cells the electrons attract solar energy. Once electrons have been transformed in conduction electrons, they are able to free themselves and distribute electric charges to the destination, those released electrons are replenished once the circuit is completed; this stage also compares to the lost of electrons during photosynthesis which are replenished by splitting water.

Even though, both processes have similitude's they have many differences, as well. Among those differences are price, amount produced, and absorption. When it comes to contrast prices, photosynthesis is advantageous, as it is abundant and inexpensive. Elements involve in the photosynthesis process are water, carbon, and minerals. The reproduction of plants is attained by natural processes that can occur in any realm. Solar panels are already composed by semi-conductive material silicon is the most common material used, which makes solar cells an expensive and a limited resource. The fact the PV solar panels are made of silicon increases its value as silicon’s production is extremely expensive. The amount produced in both processes represents a significant difference. Plants receive its energy input from the sun during the process of photosynthesis, according to Hunter plants are able to produce in mass scale via the process of Photosynthesis, “converting about 1,000bn metric tons of carbon dioxide into organic matter each year, yielding about 700bn metric tons of oxygen” (Hunter, P., 2004). Semiconductor-based solar cells provide conversions of rays into electricity. It is fair to say that via the Photosynthesis process it is possible to convert more protons to electrons, than via the semi-conductor based solar cells process. Photosynthesis pales in comparison to semiconductor-based solar cells when contrasting absorption abilities. Plants can only absorb light from the blue and red sections of the color spectrum so; they can only get a tiny fraction of photons. PV materials conversely can absorb energy from a broader portion of the color spectrum; therefore, they are able to raise more photons.

The laws of thermodynamics describe the relationship between heat, work, and energy. "The first law of thermodynamics is often called the Law of Conservation of Energy. This law suggests that energy can be transferred from one system to another in many forms. Also, it can not be created or destroyed. Thus, the total amount of energy available in the Universe is constant" (Pidwirny, M & Jones, S., 2006). The photosynthesis process can be considered a representation of the principle of conservation of energy, as plants changes energy instead of creating it. This occurs when plants transform sun’s energy into food by producing oxygen and carbohydrates. This principle also pertains to the way semiconductor-based solar cell's generates energy, since the solar panels do no create the sun’s energy, the sun rays are transformed in conduction electrons and transfer power.

The second law of thermodynamics, entropy, affirms “the amount of energy stays the same, quality of energy deteriorates” as energy is lost to the environment (Physics Planet). There is a relationship between the second law of thermodynamics and the processes of photosynthesis and semi-conductive based solar cells, as the heat absorbed from the sunlight cannot be released to the environment if released at higher temperature.

The absolute zero law, which is the third law of thermodynamics, express that is not possible to reach absolute zero. This thesis also has a connection with both processes the photosynthesis, and semi-conductor based solar cells when sun’s energy lessens the temperature also decrease , it can get to the point that cannot be possible to release energy. Consequently, the production of energy is not possible with atmospheric conditions of no sunlight and lower temperatures.

In conclusion, it can be said that both processes share many connections. Also, have differences as energy processors. However, the processes of photosynthesis and semi-conductor based solar cells are comparable when it comes to the laws of thermodynamics. Further developments are needed to use both processes as an alternative form to go green.

References

How Do You Produce Electricity From Solar Energy(2011) Retrieved

October 22, 2011 from

http://www.clean-energy-deas.com/articles/how_do_you_produce_

electricity_from_solar_energy.html

Hunter, P. (2004). The promise of artificial photosynthesis. Prosper Magazine. Energy Bulletin.

Retrieved October 22, 2011 from

http://www.energybulletin.net/node/317

PHOTOSYNTHESIS - Maricopa Community Colleges | Ten community ... (n.d.). Retrieved

October 22, 2011 from

http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BiobookPS.html

photovoltaics and photosynthesis. - JCCC Staff and Faculty Pages. (n.d.). Retrieved October 22,

2011 from

http://staff.jccc.net/pdecell/photosyn/solar.html

Pidwirny, M. (2006). "Laws of Thermodynamics". Fundamentals of Physical Geography, 2nd

Edition. Retrieved October 22, 2011 from

http://www.physicalgeography.net/fundamentals/6e.html

Why are plants green? - MSU Physics and Astronomy ... (1996). Retrieved October 22, 2011

from

http://www.pa.msu.edu/sciencet/ask_st/081496.html