Scanning near-field optical microscopy (see figure) has been employed to study energy transfer within a ternary blend of the conjugated polymers poly(9,9-dioctylfluorene) (F8), poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT), and the saturated polymer poly(methyl methacrylate) (PMMA). Although the morphology of such phase-separated blends resembles that of simple binary systems composed of a saturated and a unsaturated polymer, it was found that energy transfer between F8 and F8BT is significantly hindered by the diluting effect of the PMMA.