Probing the polymer-electrode interface using neutron reflection

We demonstrate that neutron reflection (NR) can be used to characterize polymer films deposited on indium tin oxide (ITO). When the chloro precursor to poly[2-(2(')-ethylhexyloxy)5-methoxy-1,4-phenylenevinylene] (MEHPPV) was spin-coated onto ITO NR revealed that between the ITO and the uniform polymer layer was a 20 Angstrom thick low contact zone. We found that the conversion of the chloro precursor to MEHPPV at 180 degreesC under vacuum gave a uniform film of MEHPPV with the layer of low contact between the polymer and ITO remaining. Finally, the NR profile suggests that the blueshift in the MEHPPV absorption spectrum on ITO when compared to quartz is due to polymer morphology and not incomplete conversion. (C) 2003 American Institute of Physics