Self-assembly method for controlling spatial frequency response of plasmonic back reflectors in organic thin-film solar cells

Abstract

We propose a novel colloidal lithography technique that uses a mixture of colloidal particles with a few different diameters. This technique can be used for fabricating quasi-random nanostructures whose k-space spectra can be easily controlled by using an appropriate combination of particles. We introduced such nanostructures into the back reflectors of organic thin-film solar cells, where they serve as plasmonic back reflectors for recycling the nonabsorbed transmitted light into surface plasmons. The obtained photon-to-current efficiency was enhanced by 14–20% compared with that of a flat cell.