Fabrication of Moth-Eye Nanostructure Arrays Using Roll-to-Roll UV-Nanoimprint Lithography With an Anodic Aluminum Oxide Mold

Abstract

Broadband antireflection is essential for improving the photocurrent generation of photovoltaic modules or the enhancement of visibility in optical devices. The moth-eye nanostructure is one of the most promising structures with potential for commercialization in the near future and roll-to-roll ultraviolet nanoimprint lithography (R2R UV-NIL) technique provides a solution for the commercialization due to its high speed, large area, high resolution, and high throughput. In this study, the anodic aluminum oxide (AAO) mold is used to produce the moth-eye nanostructure arrays upon a flexible polyethylene terephthalate substrate combining with R2R UV-NIL process, which provides a solution for continuous production of moth-eye nanostructure arrays cheaply. In addition, the influence of mold parameters and process parameters on the forming quality were investigated, respectively. The influence of process parameters was investigated by using the one-variable-at-a-time method, including feeding speed, imprinting pressure, and mold temperature. The qualitative and quantitative height evaluation for the moth-eye nanostructure arrays were carried out based on the atomic force microscope images. As a result, the feasibility is verified to produce moth-eye nanostructure arrays continuously with AAO mold and R2R UV-NIL technique. A rapid feeding speed of 20 m/min was possible to produce good moth-eye nanostructure arrays with mold 1, which were 300 nm in diameter, 300 nm in height. However, different forming results were observed as the mold parameters decreased including unsatisfactory demolding phenomenon and incomplete filling phenomenon. The incomplete filling phenomenon was improved to a certain extent by changing the process parameters and higher forming height was accomplished with lower feeding speed, higher imprinting pressure, and higher mold temperature. This research is beneficial to provide a direction for the industrial production of the moth-eye nanostructure arrays.