An anti-reflection (AR) moth-eye structure made of acrylic resin and deposited on a polyethylene terephthalate (PET) substrate was optimized in the wavelength range from 400 to 1170 nm; crystalline silicon (c-Si) solar cells function efficiently in this wavelength range. The rigorous coupled wave analysis (RCWA) method was used for optical simulation, and the Taguchi method was used for efficient optimization. The simulation results showed that the reflectance of the optimized structure over the above-mentioned wavelength range was less than 0.87% and that a minimal reflectance of 0.1% was observed at 400 nm. Experimental results showed that the reflectance of a fabricated moth-eye structure was less than 1.0% in the wavelength range and that a minimal reflectance of 0.55% was observed at 700 nm. A c-Si solar cell, which was enclosed in a polyvinyl butyral (PVB) layer of uniform thickness, was coated with the fabricated moth-eye film, and it was observed that the moth-eye film increased electric generation (EG) up to 15%, depending on the incident angle. Further, a daily increase in EG of up to 8.7% was estimated on a clear summer day in Japan when the moth-eye film was used. Copyright © 2010 John Wiley & Sons, Ltd.