Nano-imprinted cellulose acetate structures for light management of dye-sensitized solar cells

Advanced materials with surface patterning can improve light management in optoelectronic devices. In this work, we employed nanoimprinting lithography (NIL) using a hard polydimethylsiloxane (PDMS) mold to fabricate twodimensional periodically structured films from cellulose acetate (CA). This periodic structure was selected to scatter the light to increase its optical path. The mold features translated well to the patterned CA films, as shown by scanning electron microscopy and atomic force microscopy analyses. The films showed an average peak-to-peak distance of (750 ±40) nm and an average height of grooves of (130 ±7) nm. Optical characterization confirmed a high transparency (> 90%) in the studied 300–800 nm range. These patterned cellulose films were applied atop dye solar cells to enhance light harvesting and improve device efficiency. The application of these films increased the average short-circuit current density by 17% ±3% and efficiency by 18% ±2% of the solar devices. Our results underscore that the easy and accessible NIL method can help develop patterned cellulose films for facile light-management patterning for optoelectronic device technologies.