Fabrication of large area sub-wavelength structure for anti-reflection and self-cleaning optical plate

This study presents a low-cost method to fabricate a large area anti-reflection (AR) layer with sub-wavelength structures (SWSs) on glass substrate based on hot embossing with anodic alumina oxide (AAO) template. The multi-step anodization and widening process were employed to produce the saddle-shape structures for easy replication and less demolding issues. In our experiments, the diameter of circle-area AAO template can be extended to 8.5 cm with excellent uniformity and the depth of nanopores array ranged about 110nm ~ 350nm by adjusting the anodization duration and widening time. Then, the PMMA SWSs on the glass substrate were replicated by hot embossing with different aspect ratio AAO templates. In the optical measurement, the transmittance of SWSs layer is increased up to 96.8% and their reflectivity can be reduced from 5.7% to 0.2% in the range of visible light. In addition, the contact angle measurement of SWSs layer is 110°, a self-cleaning surface therefore achieved. According to these characterization results of SWSs layer, we have demonstrated a feasible method for fabricating a large-area template with nanopores array. Consequently, this enabling technology could be further implemented to LCD display and solar cell due to its excellent anti-reflection and self-cleaning effects.