Metamorphosis

Have you ever looked at one of those giant accounting calculators with a black strip of solar cell and wonder, “How does that tiny thing provide power miraculously just from exposure to light?”

A Calculator with a PV Cell

In every solar-powered calculators, there must be a solar cell (what we commonly call it) or a photovoltaic cell (other wise referred to as PV cells) that absorbs the light and then converts that light into electricity. If I were asked to tell you the structure of a PV cell, it can be as simple as one line. “It is composed of two layers of silicon put together and attached to metal wires which act as circuits.” However, the scientific explanation behind all these is so complicated yet so simple too that it will probably blow your mind, at least it blew my mind…

When I first read about how these PV cells worked, I was stunned. When I was still very little, I thought that these black strips of “plastic” had some really complicated structure inside and that I will never be able to understand how it operates. However, when I looked for how it worked, I realized that all the scientific theories behind it’s structure and operation isn’t afterall that confusing. We have talked about them all in class and that it just takes a little more than what we learned to comprehend this.

Click HERE for How The PV Cells are Formed

and

Click HERE for How PV Cells Work (Section Five on the Page Regarding Solar Electricity)

When these two layers of silicon, type-P and type-N, a P-N junction is created between the two layers. Further more,

How Does a PV Cell Work?

when light shines onto these layers, the photons from the light will knock some electrons out of their orbitals in the P-layer and be transferred to the N-layer through the P-N junction which will disturb the equilibrium between the two layers because those extra electrons added to the N-layer will cause the N-layer to be overly excessed with negatively charged particles and they start to repel each other. What happens later is that these particles get repeled on the N-layer but also get attracted towards the P-layer because the P-layer becomes positively charged as it loses electrons. Ultimately, those free flowing electrons will flow through the metal wires back to the P-layer. When these free flowing electrons move, they each carry a negative charge and by flowing through these metal wires, they create current which will create electricity.

However, these PV cells still cannot be fully able to replace conventional ways of generating electricity such as coal because they still aren’t effecient enough. These cells can utilize about 17%~18% of the power it absorbs from the sun and even the most advanced ones can only utilize about 40% of the sun’s power. There is still much to be done and when we are capable of fully utilizing solar energy to generate power will not only mean an outbreak in science but also in the economics too. Because it basically means high amount of energy generated at a very cheap rate. Just think about it this way, the amount of solar energy that strikes the US is enough to supply the US with enough power for one and a half year! It is a cheap source of energy that will not cause environmental pollutions… So….When will we be able to see that day when PV cells are seen everywhere used as power sources?

Works Cited