Hierarchical Artificial Compound Eyes with Wide Field-of-View and Antireflection Properties Prepared by Nanotip-Focused Electrohydrodynamic Jet Printing

Artificial compound eyes (ACEs) endowed with durable superhydrophobicity, wide field-of-view (FOV), and antireflection properties are extremely appealing in advanced micro-optical systems. However, the simple and high-efficiency fabrication of ACEs with these functions is still a major challenge. Herein, inspired by moth eyes, ACEs with hierarchical macro/micro/nano structures were fabricated using the combination of nanotip-focused electrohydrodynamic jet (NFEJ) printing and air-assisted deformation processes. The NFEJ printing enables the direct and maskless fabrication of hierarchical micro/nanolens arrays (M/NLAs) without intermediate steps. The introduction of M/NLAs on the eye surface significantly improves the water hydrophobic performance with a water contact angle of 161.1 degrees and contact angle hysteresis (CAH) of 4.2 degrees and generally decreases the reflectance by 51% in the wavelength range of 350-1600 nm in comparison to the macroeye without any structures. The contact angle remains almost unchanged, and the CAH slightly increases from 4.2 degrees to 8.7 degrees after water jet impact for 20 min, indicating a durable superhydrophobicity. Moreover, the results confirm that the durable superhydrophobic ACEs with antireflection properties exhibit excellent imaging quality and a large FOV of up to 160 degrees without distortion.

Automated summary

This study successfully fabricates artificial compound eyes with hierarchical macro/micro/nano structures, enhancing water repellency and reducing reflectance. The durable superhydrophobicity is maintained after water impact, and the artificial compound eyes exhibit excellent imaging quality and a wide field-of-view.