New manufacturing process captures more light in solar cells
By Emily Clark
October 11, 2007
October 12, 2007 In another development that aims to make alternative energy generation more efficient and more affordable, Braggone has discovered a method of capturing more light in a solar cell. The result is a new product line that greatly increases the efficiency of solar cells and allows manufacturing facilities to cost-effectively increase their capacity.
Silicon is at the core of solar cells and its "shiny" nature means that about 30% of sunlight is reflected back into the sky. To help trap as much photo energy and convert it into as much electricity as possible, the silicon must be either of very high purity or have very few defects. Over the years, this has been accomplished by introducing hydrogen into the manufacturing process.
Anti-reflective coating is also used on solar panels to reduce the amount of reflected light and until now, the anti-reflective and hydrogenation for advanced cells has been done with a Chemical Vapor Deposition (CVD) process that is costly for manufacturers.
Braggone can now introduce the same anti-reflective and hydrogenation techniques with a very simple and cost efficient spray coat, bake and repeat process. They are effectively tuning the optics of the cell by introducing nanometer thick layers of molecularly tailored materials and this means solar cell makers can have affordable passivation and anti-reflective solutions.
Dr. Paul Williams, vice president of business development at Braggone said the company is “minimizing the optical loss in solar cells and modules [by] capturing as much light as possible in the cells by taming the physics.” The new technology provides the capability to reduce the optical loss in the cell or module in addition to improving the efficiency of electrical conversion within the cell. The consequence for solar power producers is increased Mega Watt (MW) production capacities at a lower cost.
The product is used by spray coating it onto the solar cell, or glass, then curing it at an elevated temperature. The innovative new product line is not only a breakthrough for crystalline silicon makers, but can also be used in thin film photovoltaics as well as in solar module manufacturing to further improve their power output. Thin film has been a hot topic recently and could be one of the key ways to reduce costs of mass solar energy production. Other recent breakthroughs in the field include flexible modules to transform windows and buildings into solar panels and an easy-install solar system for residential customers.