Marcus Neander

Anti-Reflective-Coating Tuned for Higher Solar Module Voltage

The use of a low absorbing extra-white solar module cover glass increases the light transmission to the solar cell. Due to lower absorption over a broad wavelengths range, a low-iron extra-white glass has a significantly higher energy transmission than normal window glass. Specialized solar-grade high-transmission glasses covered with an anti-reflective coating (ARC) shows a further increase in module efficiency in the order of 2,5-3%. Besides the increased short circuit current due to increased transmission an additional advantage of a ARC is presented: a decrease in heating of the solar module during light exposure due to observed increase in reflectance for the longer wavelengths results in higher open circuit voltage of approx. 1 %

Evaluation of anti-reflection coatings on cover glasses for solar modules; getting down to the nitty gritty

Cost-efficient anti-reflection coatings on solar modules can help reduce the cost of photovoltaics. The efficiency increase that can be expected from such coatings is in the range of 2 - 3%. While this effect is noticeable and important, it is still small; and precise measurements as well as suitable experimental procedures are required if anti-reflection coatings are to be evaluated using only a small number of modules. This paper highlights optical effects related to the interface between the solar cell and the glass/EVA (lamination foil). We show by means of optical simulation that neglecting these effects can easily obscure the benefit of an anti-reflection coating.