Broadband omnidirectional antireflection coatings inspired by embroidered ball-like structures on leafhoppers

Leafhopper (Thaia rubiginosa) wings exhibit antireflection behaviors for wide viewing angles, resulting from leafhopper-generated brochosomal coatings on the wing surface. The embroidered ball-like brochosomes establish a gradual transition in the refractive index at air/wing interface, leading to the broadband omnidirectional antireflection performance. Inspired by the brochosomal coatings, this study develops a non-photo-lithography-based approach for assembling embroidered ball-like structure arrays exploiting a modified Langmuir-Blodgett technology. The average visible transmittance of a polymer film can be improved by ca. 8% at normal incidence, and improved by even ca. 24% as the incident angle reaches 75 degrees by introducing the artificial brochosome arrays. The dependence of the structure shape on the antireflection capabilities is also systemically studied in this research.