An energy cascading structure is designed in a polymer photovoltaic device to suppress recombination and improve quantum yields. By the insertion of a thin polymer interlayer with intermediate energy levels, electrons and holes can effectively shuttle away from each other while being spatially separated from recombination. An increase in open-circuit voltage and short-circuit current are observed in modified devices.

Weinheim: Wiley
Adv. Mater.
Ultrafast Spectroscopy

Tan, Z.-K., Johnson, K., Vaynzof, Y., Bakulin, A., Chua, L.-L., Ho, P. K. H., & Friend, R. (2013). Suppressing Recombination in Polymer Photovoltaic Devices via Energy-Level Cascades. Adv. Mater., 25(30), 4131–4138. doi:10.1002/adma.201300243