Solar cell offers a limitless and environmental friendly source of electricity. It is a solid state device that converts the energy of sunlight directly into electricity by the photovoltaic effect. A solar cell is able to create electricity directly from photons. The encapsulate is made of glass, clear plastic or other clear material, and seals the cell from the external environment. The contact grid is made of a good conductor such as a metal, and it serves as a collector of electrons through a combination of a favorable refractive index and thickness, Antireflective Coating (AR Coating) serves to guide light into the solar cell. Without this layer, much of the light would simply bounce off the surface. After a photon makes its way through the encapsulate it encounters the antireflective layer. The antireflective layer channels the photon into the lower layers of the solar cell. Once the photon passes the antireflective layer, it will either hit the silicon surface of the solar cell or the contact grid metallization. The metallization, being opaque, lowers the number of photons reaching the Si surface. The contact grid must be large enough to collect electrons yet cover as little of the solar cell's surface, allowing more photons to penetrate. The thin antireflective coatings in solar photovoltaic cells cause solar cells to appear blue, maximize the amount of sunlight absorbed and reduce surface defects that can lower performance. Coatings are of great importance in the solar photovoltaic market, as even the smallest improvement in efficiency leaves a significant impact on manufacturers' bottom line. The most popular coating method of vapor deposition of a silicon nitride film using silane gas can be risky because silane can ignite when exposed to air; is costly to transport, necessitates investment in special storage, ventilation and other safety measures to prevent accidents. These cells are also affected light-induced degradation that occurs once after the first 24 to 48 hours of sunlight exposure. Ajeet Rohatgi, director of the Photovoltaic Research Center at the Georgia Institute of Technology and his team have tested a new silane-free process for applying antireflective film to solar cells, developed by Montreal-based Sixtron Advanced Materials. The coating made of silicon carbide nitride material (Silexium) reduces light-induced degradation by upto 88%. Another problem is that crystalline silicon wafers, which are usually doped with boron, also contain oxygen. Boron reacts with oxygen on exposure to sunlight, resulting in a 3-5% degradation in cell efficiency. The researchers found that when the Silexium film is added, some of the carbon in the coating ends up diffusing into the bulk of the silicon wafer. They believe the carbon competes with the boron to make a bond with oxygen. Because there's less oxygen for the boron to bond with, light-induced degradation is largely avoided. Sixtron's system eliminates the silane gas hazard, relying instead on a proprietary solid polymer material that contains silicon and carbon. Using heat and pressure, the solid is converted to a less dangerous methyl silane gas during the cell-coating process. The solid-to-gas conversion takes place inside the company's gas-handling cabinet system, called SunBox, which has been designed to plug directly into industry-standard systems that exist on most cell-production lines. Sixtron Advanced Materials has introduced a patent-pending antireflective passivation coating technology that will greatly reduce the light-induced degradation problem for crystalline-silicon solar cells. The company claims to have demonstrated an 88% reduction in LID on cells treated with its silane-free Silexium coating. The company says that with appropriate process optimization, solar cells coated with Silexium films can deliver net efficiency gains to existing production lines. The precursor for the AR films is delivered to standard plasma-enhanced chemical vapor deposition equipment by the firm's SunBox silane-free gas generation system. The Silexium process technology addresses a major concern of cell and module manufacturers and provides solar cell manufacturers with a simple, low-cost solution to improve the efficiency of their products while simultaneously reducing manufacturing costs by eliminating the pyrophoric hazards of silane. Solar cells made with Silexium coatings also deliver increased shunt or leakage resistance and reduced reverse current by an order of magnitude, representing additional significant protections against cell degradation. The AR passivation coating process technology offers manufacturers a drop-in solution to the Light Induced Degradation (LID) problem that enables maximum flexibility within their silicon wafer supply chain and can result in further economic advantages to higher-priced LID reducing technologies. LID reduces the efficiency of modules in the field by up to 5% in the first few hours of exposure to the sun, significantly reducing the net energy harvest. Solar cells made with Silexium coatings also deliver increased shunt resistance and reduced reverse current by an order of magnitude, representing additional significant protections against cell degradation. Shunting, also known as leakage, occurs when small defects in solar cells create alternate pathways for the flow of electricity; reverse currents, caused by shading and low light, create “hot spots” that can permanently damage the cells. DSM Functional Coatings has announced the optimization of its KhepriCoat™ solar anti-reflective coating system. The improvements already have resulted in a significant contribution to the first multicrystalline-silicon solar panels to achieve a conversion efficiency of 17%, produced by REC and the Energy Research Center (ECN) of the Netherlands. The KhepriCoat™ solar anti-reflective coating system boosts light transmission of solar glass sheets by around 4%, resulting in a considerable improvement in solar module efficiency. This coating system offers the best performance in terms of light transmission, durability and flexibility. A dedicated research group within DSM is working on technology breakthroughs that improve efficiency while at the same time allowing significant cost reductions in solar systems. Researchers in the US have developed what they claim to be more efficient polymer solar cells. According to the researchers from Iowa State University and the Ames Laboratory, a thin and uniform light-absorbing layer can be placed on textured substrates, which increases light absorption of the cells and therefore improves their efficiency. The solar cells can capture more light within flat-topped ridges as well, as the thin layer can still be applied. The new solar panels are around 20 times more efficient than flat solar cells made from polymers. Development is still in its early stages and the university is now in the process of patenting the technology and working to licence it to solar cell manufacturers.