Figure 1: Thin-film UV-vis adsorption spectra of (I) and its blends with polystyrene.

(a) Increase in absorbance of absorption peaks at ~825 nm in polystyrene blended films (spectra normalized at ~750 nm); (b) red-shifts of ~825 nm-absorption maxima of polystyrene blended films from that of neat (I) film; and (c) Chemical structure of DPP-DTT, (I).