Deep Dive into Photovoltaic Cells
Date: 02/05/2024
Subject: Deep Dive into Photovoltaic Cells
Assessment:
I will be breaking down this: The SETO describes it as “When the sun shines onto a solar panel, energy from the sunlight is absorbed by the PV cells in the panel. This energy creates electrical charges that move in response to an internal electrical field in the cell, causing electricity to flow.”.The semiconductors consume the Energy of the light. When the semiconductor is exposed to light, it absorbs the light's energy and transfers it to negatively charged and positively charged particles, both electrons and their opposite flow are consumed by the N-type and P-type layers. The Terminals then take the electricity and with both the positive and negative, a flow is created.
In the next week, I will be investing my time heavily into learning about solar energy so I can learn more from my solar consultant mentor, Mrs Natalia Carter. The most obvious reason for using solar energy is because solar panels are pretty much an “infinite” source of energy. Also, the National Grid highlights how “The carbon footprint of solar panels is already quite small, as they last for over 25 years. Plus, the materials used in the panels are increasingly recycled, so the carbon footprint will continue to shrink.” This is a really important point because not only does it last longer than most electronics, 25 years, but they are being recycled as well which means soon they will have little to no effect on the environment.
Photoelectric Effect: The real reason the photovoltaic cells work is because photovoltaic cells have a “photoelectric effect” The most common materials for this effect to take place are monocrystalline, polycrystalline, or amorphous silicon. Wilhelm Hallwachs confirmed this finding when He showed that UV light shining on an evacuated quartz bulb with two zinc plates acting as electrodes and connected to a battery generated a current due to the photoelectric current (electron emission). Stoletov’s law (the “first law of photoeffect”) states that there is a connection between the intensity of electromagnetic radiation acting on a metallic surface and the photoelectric current. Crystals like monocrystalline and polycrystalline are the best materials for collecting the photoelectric current as far as we know, and silicon is a light material that works for making semiconductors. Because of the photoelectric effect, vacant spots for electrons within the crystal and silicon semiconductors allow for a steady collection of electrons from the solar panels. Powers and Beyond describe it as “When these PV solar cells are exposed to light photons, they hit the negatively charged electrons inside the silicon atoms and hit electrons and knock them loose. When this happens, it leaves behind an empty, positively charged “hole” where the negative charge used to be.”
The Electromagnetic Field: There is also a field to the solar panels to allow a current to develop. P&B states that “In untreated silicon, electrons would just recombine with these holes to produce waste heat; no electricity would be generated. To get around this and make a working solar cell, the crystalline silicon wafers are treated (doped) with two other elements: boron and phosphorus. When the boron and phosphorus meet, they interact with the silicon to create an electrostatic field just under the front surface of the cell. This field remains in the crystal structure permanently. Not, when sunlight photons hit the crystal, the negative electrons and positive “holes” are kept separate by this electrostatic field. This causes electrons to flow to the front of the cell while the holes flow to the back, creating a current.”
As more research is done and more panels move to increased complexity and efficiency, soon panels will be able to power most of the world. As this development continues, I plan to work with Mrs. Carter so that I am prepared to be in the know and take advantage of the growth coming from the solar panel world.
James, Luke. “The Photoelectric Effect and Its Role in Solar Photovoltaics.” Powers and Beyond, www.power-and-beyond.com/the-photoelectric-effect-and-its-role-in-solar-photovoltaics-a-ed89bb3f856ceb245963a222daebeb5d/.