Study of surface photovoltage spectra of MEH-PPV

Surface photovoltage spectra studies are performed on thin films of poly[2- methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] in order to determine its photoelectric properties. We find that a localized subgap electronic t ransition causes the photovoltaic response with polarity opposite to that f rom the band-to-band electronic transition (pi-pi*). This transition is fro m the valence band to a local state in the conduction band. (C) 2001 Elsevi er Science BN. All rights reserved.