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