Ultrafast energy-transfer dynamics between block copolymer and π-conjugated polymer chains in blended polymeric systems

The blending of polymers has been conventionally employed to increase the quantum efficiencies of polymeric electroluminescence (EL) devices via the energy transfer process, which was interpreted in terms of the Forster-type energy transfer based on dipole-dipole interactions. The detailed analysis of various time-resolved spectroscopic data in the blended polymer between MEH-PPV (poly [2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene]) and DSiPV (poly[1,3-propanedioxy-1,4-phenylene-1,2-ethylene(2,5-bis(trimethylsilyl)-1,4-phenylene)1,2-ethylene-1,4-phenylene]) provides some evidence that the ultrafast energy-transfer channel via the shortest interchain distance between the adjacent constituent polymer chains should be considered to account for the dynamics of stimulated emission (SE) and photoinduced absorption (PA) in the blended polymeric systems. These interchain interactions are also responsible for the diminishment of SE of the blended polymer in the transient absorption spectra, because PA is enhanced due to the formation of interchain excitons. These results provide new insight into the role of interchain interactions in the improvement of heteropolymeric EL devices.