Anti-reflecting and photonic nanostructures

The role of random nanostructures for the omnidirectional anti-reflection properties of the glasswing butterfly

“…According to the famous study of Bernhard and Miller 18 in the 1960s, the index of refraction changes gradually in the moth eye due to submicroscopic nipples, and such structuring reduces the reflection of light. In the meantime, this principle has been also found in eyes 19 and wings 5,6 of other insects, and can be applied for the fabrication of biomimetic artificial anti-reflection coatings 20,21 . All these nipple structures, however, feature a highly periodic distribution with constant height and aspect ratios of 1 to 2.…”

“…ARTICLE It explicitly considers the random height distribution of the nanopillars. We start with the calculation of the effective volume fraction f(z) of the wing material similar to the previous studies of gradient refractive index anti-reflective structures [20][21][22] . The subsequent application of the effective medium theory 23,24 allows the calculation of the refractive index profile of the random nanopillars.…”

“…The subsequent application of the effective medium theory 23,24 allows the calculation of the refractive index profile of the random nanopillars. Afterwards, the transfer matrix method (also known as the multilayer model) 20,22,24,25 enables us to compute the reflection and transmission for a given polarization and for all angles of incidence.…”

“…By optimizing the variance of the distribution and the shape of the pedestals, almost perfect antireflection surfaces can be engineered for a broadband range of wavelengths and a wide range of viewing angles. Such antireflective surfaces could be adapted to improve the light collection in solar cells or for an efficient light extraction of the substrate modes in light-emitting diodes or even enhancing the performance of the optical, optoelectronic and electro-optical devices, such as glasses, mirrors, lens, photodetectors, surface-emitting lasers, displays and optical sensing or imaging 20,21,[30][31][32] .…”

Efficiency Enhancement of PEDOT:PSS/Si Hybrid Solar Cells by Using Nanostructured Radial Junction and Antireflective Surface

“…To achieve high light absorption and conformal polymer spin coating, the nanostructures on the Si surface should be smaller than the wavelength of incident light. 18,19 The formation of a tapered nanostructure profile is preferred. 13,25 The pillar structures, which is referred as the NS1 structure in this paper, has a 100 to 200 nm diameter and 100 nm depth (scanning electron microscopy (SEM) image, Figure 2a).…”