PICOSECOND TIME-RESOLVED PHOTOLUMINESCENCE IN MEHPPV - SOLUTION, FILM, GEL AND BLEND

We present the results of time resolved luminescence studies of poly(2-methoxy,5-(2'-ethyl-hexloxy)-p-phenylene-vinylene), MEH-PPV, as a pure film, in solution, in an ultra-high molecular weight polyethylene (UHMW-PE) gel, and in a blend with UHMW-PE. The room temperature luminescence has a characteristic lifetime of 200-300ps, and the 80K luminescence has a characteristic lifetime of 400-600ps. These times are independent of the physical form of the material, contrary to our expectations of enhanced luminescence efficiencies (and therefore lifetimes), in solution. The short lifetimes (compared to intrinsic lifetimes calculated from absorption and emission spectra) indicate the importance of non-radiative decay routes. The decay profile of the PL is found to differ from a single exponential for MEH-PPV at room temperature. Integrated luminescence verses pump intensity data are also presented.