**8.3 Thin films**

Thin films will be developed to become a reliable and more efficient source for solar energy application. The principle of its applicability in the solar energy application is discussed under spectral selectivity properties of a surface in solar energy application. An organic solar cell is an example of such thin films. Solar electric thin films are lighter, more resilient, and easier to manufacture than crystalline silicon modules. The best developed thin film technology uses amorphous silicon in which the atoms are not arranged in any particular order as they would be in a crystal. An amorphous silicon film, only one micron thick, absorbs 90% of the useable solar radiation falling on it. Other thin film materials include cadmium, telluride and copper indium dieseline. Substantial cost savings are possible with this technology because thin films require little semiconductor materials. Thin films are also produced as large complete modules. They are manufactured by applying extremely thin layers of semi conductor materials unto a low – cost backing such as glass or plastics. Electrical contacts, anti-reflective coatings, and protective layers are also applied directly to the backing materials. The films conform to the shape of the backing, a feature that allows them to be used in such innovation product as flexible solar electric roofing shingles.
