Figure 1

(a) Chemical structures of PffBT4T-2OD polymer, PC₇₀BM and bis-PDI small molecules, (b) energy level diagram of the inverted device structure with active materials used, (c) normalized UV-vis absorption spectra for the PffBT4T-2OD polymer, PC₇₀BM, bis-PDI, PffBT4T-2OD:PC₇₀BM and PffBT4T-2OD:bis-PDI thin films.