Dragonfly-Wing-Inspired Inclined Irregular Conical Structures for Broadband Omnidirectional Antireflection Coatings

Abstract

Blue-tailed forest hawk dragonfly (Orthetrum triangulare) wings exhibit a high transparency at wide viewing angles. The broadband omnidirectional antireflection behaviors of dragonfly wings result from the random arrangement of inclined irregular conical structures. In this study, a scalable colloidal lithography technique is developed for spin-coating randomly packed silica colloids, which serve as direct structural templates for patterning subwavelength inclined conical structures on substrates. The dragonfly-wing-inspired structures feature an omnidirectional antireflection performance over the whole visible spectral range and generate superhydrophobicity after surface functionalization. The dependencies of the inclination and height of the conical structures on the antireflection performance and self-cleaning property are also systemically studied in this research.

Carbon Nanomaterials Modified Biomimetic Dental Implants for Diabetic Patients

“…The dragonfly surface is superhydrophobic with a 153 • and above water contact angle [19,102]. Unlike the cicada, the protrusions are irregular and conical [58], and reported to be varying among different species with a range of 70 to 195 nm [19,103,104]. The dragonfly wing structures are active against both gram-positive and gram-negative bacteria [105] and exhibit both antibacterial and antifouling properties [106].…”

Broadband Enhancement of Anti-reflectivity for a High Angle of Incidence Using Nanocone Geometry

“…The use of surface nanostructures to achieve wide-angle and broadband antireflective (AR) effects is a fascinating method learned from nature, which can improve the performance of optical devices such as photovoltaics, light-emitting diodes, optical lenses, and display panels. − AR nanostructures observed from diverse insects such as moths, , butterflies, cicadas, and dragonflies can form an optical interface in which the refractive index (RI) changes gradually. Therefore, light absorption or transmission increases not only for the broadbands of wavelengths but also for the wide angles of incidence (AOIs) when compared with the use of a quarter-wave thin film. ,,, Furthermore, the AR nanostructure provides additional useful functionalities to optical devices, such as self-cleaning, anti-fogging, and anti-bacterial effects. − …”

Antireflection layer of ZnO nanorod embedded in PDMS film for enhancing omnidirectional photovoltaic performance of CIGS photovoltaic cell

“…7 In the past years, SWG structures have been extensively studied as substitutes for a single-layer or multilayer ARLs. 8,9 SWG structures have been developed to have excellent broadband and omnidirectional anti-reflective optical properties. Different manufacturing processes have been used extensively to fabricate SWG structures that include electron beam lithography and dry etching.…”

“…The subwavelength grating (SWG) structure of moth‐eye pillars was discovered by Bernhard in his 1967 study 7 . In the past years, SWG structures have been extensively studied as substitutes for a single‐layer or multilayer ARLs 8,9 . SWG structures have been developed to have excellent broadband and omnidirectional anti‐reflective optical properties.…”