Photoluminescence of oligomer and polymer blends

We have measured the photoluminescence(PL) of polymer and oligomer blends using partially converted poly-(p-phenylene vinylene) (PC-PPV) and a kind of p-phenylene vinylene oligomer, 1,4-distyrylbenzene in the solution of N-methyl-2-pyrrolidinone (NMP). The PL spectra of this blended material showed that the amounts of oscillator strength of oligomer peak at 2.79eV shifted to red, near 2.49eV, which is responsible for PC-PPV. This changing of oscillator strength results the enhancement of initially weak PL intensity of PC-PPV and eventually changing the color. In order to explain the excitonic migration effect occurring more seriously in blended system, as we believed, we compared this data to that of PC-PPV/oligomer multi-layered film as well as of oligomer itself. Those results will be also compared with that of another blended material, oligomer and polyaniline(PANI), and the differences will be discussed.