Chemistry

Guide to Solar Photovoltaic Cells



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Here Comes the Sun: Advancements That Could Give Way to a More Sustainable Energy of the Future
We have all seen them before, the glass rectangles perched upon the roofs of homes, making them stick out like sore thumbs while we try to keep our eyes focused on the highways. Some have heard even more about these "solar panels," which use energy from the sun and lessen our dependence on coal-based electricity. They're just supposed to be like the calculators with that strip of plastic on top that never ran out of batteries.
Yet, if they really were as simple and nice as advertised why don't more people have them? Why do the majority of the people still rely on electricity, the production of which continuously releases carbon into the atmosphere? The answer is simple: solar panels, as clean and seemingly noble as they are, just don't make sense for the average American household in the hustle and bustle lifestyle of the 21st century.

First, we have to understand how solar panels function. They are usually a sheet of semiconducting material, usually silicon. Large amounts of silicon are held together through covalent bonding, where the electrons are shared between the silicon atoms, which normally have 4 electrons in the outer shield and need eight to be stabilized. However, when little packets of energy from sunlight, called photons, hit these atoms, the electrons are given more energy to float around, faster and farther from the nucleus. Thus, the electron becomes "excited." Eventually, an electron leaves its orbit around the atom, giving it a positive charge (because a negative electron left) and the electron itself goes free floating. The charge of the atoms create gradients, and the traveling of the electron through the gradient creates energy, which then can be harvested in the form of DC by an array of these sheets called solar panels. An inverter can be used to change these into the AC (alternating current) needed for home appliances.

That is the scientific gibberish describing the way solar panels work, but that still leaves the question as to why they aren't more popular. As of right now, solar panels are extremely expensive, and given their size, are inefficient. Each photovoltaic panel works at around 40% efficiency, and, thus, many are needed to power a household. Aside from the cost of the panels, installation prices are usually five figuresenough to drive away the casual consumer.
However, new technology in the market might bring a change to this. Colorado State University has developed a new method that can result in low-cost, high-efficiency solar panels. Instead of using expensive crystalline silicon, the solar panels will be made of cadmium telluride thin film, a more widely available resource. The cost to buyers would be brought down to about $2/watt, a figure that would make solar panels about half as expensive as they are. Not to mention, maintenance on these will be easier due to their lower costs, and only 2% of the materials will need to be recycled. When these things finally are mass produced, which is expected to happen towards the end of the year, an era could dawn where sustainable energy is within our reach.

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