Disordered diffraction gratings tailored by shape-memory based wrinkling and their application to photovoltaics

Quasi-periodic surface wrinkles prepared by an all-polymer process are introduced for improved light harvesting. The wrinkles' diffractive properties, as well as their external and internal reflectance, are analyzed experimentally and numerically. By applying the surface wrinkles as a coating on planar heterojunction crystalline silicon solar cells, we demonstrate an increase in light absorption due to the improved in-coupling of the incoming photons and to the recapturing of some of the light reflected on the solar cell front side. Furthermore, surface wrinkles prevent glare effects that are commonly experienced with periodic diffraction gratings. The up-scalable wrinkling process allows the adjustment of the diffraction properties of our structures, which might be exploited for different photovoltaic technologies.