Fig. 4. (a) Peak normalized thin-film UV-visible spectra (obtained from recording both specular reflection and transmission) for P3OT–PFB, P3OT–PFB–S–Coumarin₃₄₃, and Coumarin₃₄₃–SH dispersed in a polystyrene matrix (9 wt%). Films spun from THF (5 mg mL^–1) (b) schematic representation of P3OT–PFB–S–Coumarin₃₄₃ illustrating the likely route of interchain energy transfer and emission from P3OT.