Effect of residual solvent and thermal annealing on a light-emitting polymer-based electrochemical cell

摘要

The effect of residual solvents and thermal annealing on light-emitting electrochemical cells constructed using poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] and poly(ethylene oxide) (PEO) doped with lithium trifluoromethanesulfonate (Li triflate) was investigated. The turn-on voltage dropped when the films were annealed in dry and vacuum atmospheres. This is attributed to the removal of residual solvents that are detected by mass spectrometry in ultrahigh vacuum. The results are interpreted in terms of a model in which ionized Li triflate has higher ionic conductivity in the presence of dry PEO than when solvated by water or cyclohexanone within a PEO matrix.