Electrical and optical properties of light emitting electrochemical cells using MEH-PPV/PEO:lithium-salt blends

Light emitting electrochemical cells (LECs) were prepared with poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) and poly(ethylene oxide) (PEO) complexed with lithium triflate (CF3SO3Li) in different blend compositions. Atomic force microscopy (AFM) images were performed to observe the influence of the blend composition in the film morphology. UV-Vis absorption and photoluminescence spectra were used to characterize the blends, and current-voltage curves and electroluminecent measurements were carried out to study the device performance. A correlation between the blend morphology and the electrical performance of the devices were also studied. Optical and electrical results of LEDs made of pure MEH-PPV were presented for comparison with the LEC devices.