PHOTORESPONSES OF A POLYMER-BLEND DEVICE

We report the results of the photoconductivity measurements of the pol ymer-based diode formed with polymer blend of poly[2-methoxy,5-(2'-eth yl-hexoxy)-1,4-phenylene vinylene] (MEH-PPV) and enyllene-(2,5-bis(tri methylsilyl)-1,4-phenylene)-1 ,2-ethenylene-1,4-phenylene] (called B-p olymer). The local peak around 2.87 eV in the spectral response of pho tocurrent indicates the possibility of the excitation from the HOMO le vel of MEH-PPV to the LUMO level of B-polymer. From these results, we can conclude that the photocurrent and electroluminescence are origina ted from the rectified microjunction formation in the polymer blend, n ot from the energy transfer mechanism.