Dependence of field-effect hole mobility of PPV-based polymer films on the spin-casting solvent

We present field-effect mobility measurements on a conjugated polymer poly(2-methoxy-5-(3',7'-dimethyloctyloxy)1,4-phenylenevinylene) (MDMO-PPV) that was spin-cast from different solvents. The organic field-effect transistors were fabricated using an Al/p(+)-Si/SiO2/TiW/Au/MDMO-PPV configuration. The hole field-effect mobilities for MDMO-PPV deposited from a toluene and chlorobenzene solution were found to be 5 x 10(-6) and 3 x 10(-5) cm(2)/(V S), respectively, as calculated from the saturation regime. These results are explained on the basis of a modification of the polymer morphology caused by using different solvents, as evidenced by light scattering experiments on the MDMO-PPV solutions. (C) 2002 Elsevier Science B.V. All rights reserved.