Applications

There are many photovoltaic technologies in the market today, however, two types constitute the majority of installations. The most widely used technology is poly and mono-crystalline silicon. The next most common, and fastest growing, technology in the PV market is thin film PV. Concentrating PV systems are a developing technology and have applications in certain parts of the world where there is high direct solar radiation, such as the desert Southwest in the United States.

Poly and Mono-Crystalline Silicon These modules use a glass cover to protect the thin, fragile silicon solar cells. Like most PV technologies, the glass is bonded with an optical adhesive to the top of the solar cells. Therefore, the outside surface that directly faces the sun requires an anti-reflective coating treatment to maximize the transmission of useful energy to the solar cell. The anti-reflective coating must have exceptional durability, as it is exposed to the sun’s intense radiation and all weather extremes for several decades. Additionally, the coating must not adversely affect the appearance of the PV module. And finally, the coating must have a superior ability to increase the electricity output of the module at a cost that is economically viable. Thin Film PV This technology involves very sophisticated manufacturing systems similar to those used in the semiconductor and flat panel display businesses. The ability to convert sunlight to electricity is not as great as with the crystalline technologies, but the cost of manufacturing thin film PV is very low, making thin film an attractive alternative if the installation area is not a constraint.  Similar to the crystalline module application, an anti-reflective coating can be applied to the outside, or the exposed side of the glass surface to increase conversion efficiency. Concentrating PV Systems There are a number of ways that sunlight can be concentrated using both reflection and refraction (bending light). Once concentrated, this solar energy is focused onto PV cells to generate electricity. With most concentrating systems there are one or more locations where energy losses can occur, thus reducing the amount of electricity that the system generates. Like the other PV applications, an anti-reflective coating can be applied on one or both sides of the cover glass to increase conversion efficiency.

Solar thermal systems direct the sun’s energy into a thermal storage medium, usually water or some other liquid.  This thermal energy is then used directly, such as hot water for home use, or indirectly, to run a turbine for electricity generation, . Because these systems concentrate energy, an anti-reflective coating is highly desirable for maximizing system performance.