Solar cells, camera lenses, and LEDs could benefit from new antireflection coatings.Unwanted reflections limit the performance of light-based technologies, such as solar cells, camera lenses, and light-emitting diodes (LEDs). In solar cells, for example, reflections mean less light that can be converted into electricity. Now researchers at Rensselaer Polytechnic Institute (RPI), in Troy, NY, and semiconductor maker Crystal IS, in Green Island, NY, have developed a new type of nanostructured coating that can virtually eliminate reflections, potentially leading to dramatic improvements in optical devices. The work is published in the current issue of Nature Photonics.
The researchers showed that they can prevent almost all reflection of a wide range of wavelengths of light by "growing" nanoscale rods projected at specific angles from a surface. In contrast, conventional antireflective coatings work best only for specific colors, which is why, for example, eyeglasses with such coatings still show faint red or green reflections. Fred Schubert, professor of physics and electrical, computer, and systems engineering at RPI and one of the authors of the study, says that the material stops reflections from nearly all the colors of the visible spectrum, as well as some infrared light, and it also reduces reflections from light coming from more directions than conventional coatings do. As a result, he says, the total reflection is 10 times less than it is with current coatings.
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