Solar Cells - An Intro and Overview

To understand the field of solar energy, one must begin with solar cells (otherwise known as photovoltaic cells.) Basically, these are devices that convert light directly into electricity. The photovoltaics market is generally invested in the manufacture of cells made of wafer-like pieces of silicon. Typically, many individual cells are assembled together in frames, forming a solar array. There are currently three types of solar cell commonly available for practical residential and personal use.

The cheapest and least efficient type of solar cell is known as amorphous silicon. This is a form of silicon that can be applied to a material (usually glass) in a thin film. It is therefore much cheaper to manufacture. A strong disadvantage of this material is that it lacks the well-ordered crystalline pattern of other forms of silicon, and features a large drop-off in conversion efficiency.

The highest efficiency comes from monocrystalline silicon cells, constructed of single crystals cut from large cylindrical ingots, resulting in circular wafer-like cells. This rounded shape comes with one disadvantage: multiple cells can't be framed snugly together, resulting in some wasted space. This raises some contention as to whether or not, when framed together in a larger arrays, these cells produce notably more electricity than the polycrystalline cell variety. Panels made with monocrystalline cells also come with a higher price tag.

Based on sales, the most common type of photovoltaic cell is polycrystalline. These are made from multiple silicon crystals and cut into square wafers to be mounted together in an array. They are cheaper and easier to manufacture than monocrystalline cells, but slightly less efficient.

Solar power is one of the fastest growing fields in energy production, and new developments are being made all the time. R&D labs around the world are developing cells boasting higher conversion rates. Panels are being developed made from cheaper forms of silicon, and a process has even been developed to recycle or "re-purpose" suitable material from scrapped semiconductor wafers. The AIST, a Japanese research facility, has been able to develop transparent panels that convert UV light into electricity while allowing visible light to pass through. Such a material could one day be used to replace windows. Bottom line, solar energy is a massive field, and the small, unassuming solar cell has the potential to carry the world into a cleaner and easier future.

Edmund E. Taylor has researched and writes on a number of topics including solar energy, the green movement, renewable resources and recycling. His background is in teaching and higher education. For more of Edmund's articles on green energy, please visit PV Power, a supplier of residential and commercial solar power information.