The light collection in thin film polymer solar cells is substantially improved by application of a textured retroreflective foil, which reduces primary reflection and outcoupling of unabsorbed light. Consequently the external quantum efficiency (EQE) improves over the whole sensitivity range and the power conversion efficiency is improved by as much as 19%.
Esiner, S., Bus, A. B. P., Wienk, M. M., Hermans, K., & Janssen, R. A. J. (2013). Quantification and validation of the efficiency enhancement reached by application of a retroreflective light trapping texture on a polymer solar cell. Advanced Energy Materials, 3, 1013-1017. https://doi.org/10.1002/aenm.201300227