Temperature dependence of the spectral line narrowing and photoluminescence of MEH-PPV

We present an investigation into the temperature dependence of the spectral line-narrowing (SLN) behaviour of poly[2-methoxy, 5-(2'-ethyl-hexyloxy)-1, 4-phenylene vinylene] (MEH-PPV) and correlate this with measurements of the photoluminescence (PL) spectra as a function of temperature. These measure ments were made with films spun from tetrahydrofuran (THF) which is the pre ferred solvent for line narrowing, and from chlorobenzene (CB). We observe a blue shift in the peak position of the SLN as the temperature is increase d from 77 to 277 K. The Pi, spectra show a similar trend; however, for film s spun from both THF and CB the PL spectra deviate from the SLN data, espec ially at high temperatures. Possible explanations for the difference in beh aviour of PL and SLN in films spun from the two solvents are discussed, inc luding the role of conformational disorder. (C) 2000 Elsevier Science S.A. AU rights reserved.