Large Enhancements in Optoelectronic Efficiencies of Nano-plastically Stressed Conjugated Polymer Strands

The photoluminescence (PL) of well dispersed molecules of a conjugated polymer, poly[2-methoxy-5-((2'-ethylhexyl)oxy)-1,4-phenylene-vinylene] (MEH-PPV), in an optically inert matrix manifested dramatic increases when the individual molecular strands were fully stretched. The PL increase rose with stretching and may reach several folds when the mechanical strain of the matrix polymer went beyond 550%. Strong polarization effects indicate that stretching individual polymer chains was responsible for the PL enhancement. This effect was attributed to suppression of electron-phonon interactions in the stress-rigidified polymer chain segments and may be useful for efficiency-enhanced polymer-based optoelectronic devices.