Jan 5, 2010

Types of Solar Cells

Solar power is electricity generated through photovoltaic cells, commonly known as solar cells. While solar cells were first developed in the mid-1900s by NASA to power spaceships, science has come a long way since then. Now, three different types of solar cells exist:

Single Crystal Solar Cells – First Generation

As the name suggests, each cell is made from a slice of a silicon crystal, which is made by purifying, melting and freezing silicon. You can imagine these slices would be flat and smooth, so they need to be mounted within rigid frames, and since the process is so painstaking, the each solar cell is pretty expensive. Despite this, they’re the most popular type of solar cells because of highly efficient nature.

These types of solar cells are also referred to as monocrystalline cells. The above image shows a single crystal solar cell (credit, Affine Financial Services).

Thin film Solar Cells – Second Generation

These are made of microscopic layers of amorphous silicon (non crystal silicon) placed upon plastic, glass or metal, which may make them flexible enough to double as roof tiles. Although these are cheap to manufacture, their efficiency levels are very low and their output actually falls by 15% within the first few weeks of exposure to sunlight. The second name for these cells is amorphous silicon cells (image credit, Solar Panels Power).

Multi Crystal Solar Cells – Third Generation

Also known as polycrystalline cells, these are a slight variation of single crystal solar cells in that they are made of slices cut out of blocks of several silicon crystals, as opposed to single silicon crystals. This results in lower prices and efficiencies but the cost-advantage outweighs losses in output so it’s a win-win situation. Just like monocrystalline cells, they need to be framed within a rigid structure (image credit, Shen Zhen Estate).

UPDATE: There is no a fourth type of solar cell called the holographic thin-film cell, a major breakthrough in technology. Read more about it here.

While the prices of solar cells continue to fall each year, plenty of advancements in technology need to be made before solar power gains widespread popularity. But that doesn't seem like a far-off destination because education in the area of solar technology is gaining popularity. One day, that too will happen and man will eventually fully utilize the potential of the Sun as a source of power.

Sources: NREL, Solar Power Answers, Solar Botics