Connection between the conformation and emission properties of poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] single molecules during thermal annealing

摘要

We investigated the transitions of conformations and their effects on emission properties of poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) single molecules in PMMA matrix during thermal annealing process. Total internal reflection fluorescence microscopy measurements reveal the transformation from collapsed conformations to extended, highly ordered rod-like structures of MEH-PPV single molecules during thermal annealing. The blue shifts in the ensemble single molecule PL spectra support our hypnosis. The transition occurs as the annealing temperature exceeds 100 ℃, implying that an annealing temperature near the glass transition temperature T_g of matrix is ideal for the control and optimization of blend polymer films.