Spectrally selective antireflection of nanoimprint lithography-formed 3D spherical structures on film coated with a silver layer

We fabricate moth-eye antireflection (AR) coatings using high-resolution and low-cost UV nanoimprint lithography with polyethylene terphthalate (PET) molds. Several various thicknesses of silver films placed on the moth-eye structure were analyzed for reflectance and transmission. On PET, the conical nanostructured surface arrays had a spatial period length of approximately 250 nm, a diameter of approximately 200 nm, and a height of approximately 160 nm. After them, a silver (Ag) layer of 18 nm is deposited satisfactorily on the PET substrate surface. The never-ending moth-eye formations of the imprinted mold were fabricated by Ni mold electroplating, interference lithography, and replication. We found that an Ag layer of suitable thickness on AR film in the spectrum range that can be seen has high transmittance (Highest value is 72%) while in the infrared spectrum it has high reflectance (At least 60%). For an optical film with a silver coating has been placed on an anti-reflection subwavelength-structured (ASS) surface, such properties, including heat insulation, have obvious applications in windows for homes and vehicles.