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Silicon is commonly used to make solar cells due to its special chemical properties. A silicon atom has 14 electrons that are arranged in three different shells.

The first two shells which have two and eight electrons each are completely full. However, the outer shell is only half full as it only has four electrons. Thus a silicon atom is always on a look out for ways to fill up its last shell.

In order to do this, it will have to share electrons with four nearby atoms to gain stability. It is just as if each atom has joined four hands to four neighbors. This is what forms the crystalline structure, leading to the formation of a PV cell.

However, pure crystalline silicon has the issue of being a poor conductor of electricity as it does not have any free electrons that can move about, as in the case of more optimum conductors like copper.

To solve this problem, the silicon in a solar cell has impurities added, which alters its working.

When pure silicon is supplied some energy, for example in the form of heat, the energy can be used by a few electrons to break free of their bonds and leave their atoms. This leaves a hole behind in each case. The free electrons, called free carriers, then roam around freely around the crystalline lattice looking for another hole to fall into and carrying an electrical current. But their small number in pure silicon don’t make them much useful.

However, when pure silicon is mixed with phosphorous atoms, it takes much less energy to loosen the “extra” phosphorous electrons as they aren’t tied up in a bond with any neighboring atoms. As a result, most of these electrons do break free, and we have a lot more free carriers than we would have in pure silicon.

This adding of impurities is called doping, and when doped with phosphorous, the resulting silicon is called N-type (“n” for negative) because of the prevalence of free electrons. The N-type silicon is a better conductor as compared to pure silicon.

Another part of a typical solar cell is doped with the element boron, which has only three electrons in its outer shell instead of four, in order to form the P-type silicon.A P-type (“p” for positive) has free openings and carries the opposite (positive) charge.

The interaction of the both enables the easy flow of electricity, enabling sunlight to be transformed into electric energy.

Technorati Tags: Silicon,Solar,Cell,atom,conductor,energy,crystalline

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Silicon is commonly used to make solar cells due to its special chemical properties. A silicon atom has 14 electrons that are arranged in three different shells.

The first two shells which have two and eight electrons each are completely full. However, the outer shell is only half full as it only has four electrons. Thus a silicon atom is always on a look out for ways to fill up its last shell.

In order to do this, it will have to share electrons with four nearby atoms to gain stability. It is just as if each atom has joined four hands to four neighbors. This is what forms the crystalline structure, leading to the formation of a PV cell.

However, pure crystalline silicon has the issue of being a poor conductor of electricity as it does not have any free electrons that can move about, as in the case of more optimum conductors like copper.

To solve this problem, the silicon in a solar cell has impurities added, which alters its working.

When pure silicon is supplied some energy, for example in the form of heat, the energy can be used by a few electrons to break free of their bonds and leave their atoms. This leaves a hole behind in each case. The free electrons, called free carriers, then roam around freely around the crystalline lattice looking for another hole to fall into and carrying an electrical current. But their small number in pure silicon don’t make them much useful.

However, when pure silicon is mixed with phosphorous atoms, it takes much less energy to loosen the “extra” phosphorous electrons as they aren’t tied up in a bond with any neighboring atoms. As a result, most of these electrons do break free, and we have a lot more free carriers than we would have in pure silicon.

This adding of impurities is called doping, and when doped with phosphorous, the resulting silicon is called N-type (“n” for negative) because of the prevalence of free electrons. The N-type silicon is a better conductor as compared to pure silicon.

Another part of a typical solar cell is doped with the element boron, which has only three electrons in its outer shell instead of four, in order to form the P-type silicon.A P-type (“p” for positive) has free openings and carries the opposite (positive) charge.

The interaction of the both enables the easy flow of electricity, enabling sunlight to be transformed into electric energy.

Technorati Tags: Silicon,Solar,Cell,atom,conductor,energy,crystalline

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• Using Solar Electricity In Your Garden
• Solar Power Goes Underground
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Having dished out plenty of solar power info, I got to think whether or not the majority of people are even unaware of the brains behind the project, the Solar Panel? Whatever the metaphor, lets familiarize us with the photovoltaic physical workings of this super hero enigma.

How They Do And What They Do?

As mentioned, the principles of photovoltaic physics are used to convert the energy of the sun in to electricity rather than just heat. Now the impressive scientific stuff has been duly noted, let me paint a much simpler picture.

Solar cells are not made using pure silicon but instead have impurities added to it. Why? Because pure silicon crystals are non reactive in a stable state, which is not good as the electrons need some form of instability to be productive. So in this context some impurities must be required.

The 2 different kinds of silicon are layered in sheets that have electrical connections on either side, one of which will generally give up the electrons and the other accepts them. This movement of electrons is further initiated in to traveling in circuit to produce energy when sunlight hits the silicon panel. No noise, no movement, no muss no fuss quite frankly. Maintenance is a doddle if ever required too. And thanks to numerous and constant engineering advances, efficiencies are on the rise and costs are going down. Those living in areas far from the power grid find it more economically viable to use solar rather than the high expenses of wiring up their homes.

And that’s good because?

Well, how about the fact that it can be generated and used at the same point for one? You don’t lose a lot of the energy as you would from other sources which lose huge quantities of energy as heat. Although you will have seen power plant style fields of mass solar energy generators. Solar panels are great for domestic uses as at least it contribute to your existing grid supply. Every little helps right? Aside from standard solar panels, you can even find roof shingles that have photovoltaic capacity that can replace existing roof shingles without requiring separate solar panels!

But, in the interest of fairness, you do have to know that solar energy would have to be stored so that it can run throughout the sun-less hours too. There are lots of ways to do this though, some of the most common being

1. Store in batteries.

2. Heat can be stored in thermal mass for electricity generation later.

3. Some can even use the electricity during sunshine hours to pump water uphill, which runs back downhill through a turbine to generate electricity.

Just think about it, even if you aren’t the wacky-white-haired genius himself, it doesn’t take much to realize that the abundance of energy given off by the sun can and should be put to brilliant use.

Technorati Tags: Solar,Panel,energy,generators,panels,batteries,photovoltaic,silicon,electrons,shingles

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