Researchers from Lawrence Livermore National Laboratory (LLNL) recently found a new technology alternative to anti-reflection coatings in order to address the desire in solar cells to minimize reflectivity, absorbing more sunlight and thus, generating more electricity.
The technology is based on biomimicry concept that duplicates the hierarchical structure of a moth’s eye, which is known for superb navigation in darkness through its excellent absorption of light, by incorporating layers of micro- and nanostructures on silicon’s surfaces, resulting in a reduction in reflectivity by 1 to 2%, regardless of incident light’s angle.
The latter allows solar cells to trap more light at all angles, unlike current solar cells that require tracking of sun’s position to maximize light absorption.
The team, headed by Anna Hiszpanski and Juan Diaz Leon, came up with guidelines or design rules for the minute hierarchical structures that can be customized depending on the application and desired degree anti-reflectivity.
“We found that by combining moth-eye structures of different sizes, you can not only reduce reflections at the wavelength region they are supposed to operate (following the previously known rule of thumb), but you can also further reduce reflections at a given wavelength range,” explains Diaz Leon.
Hiszpanski further discussed that aside from solar cells, the technology can be applied to eyeglasses, eliminating reflectivity and glare without the green or purple effect produced in current anti-reflective coatings of ophthalmic lenses. Moreover, it could enable cameras to take photos at a lower light and also find its application in telescopes and diffraction optics.