Photoelectron emission from conjugated polymer films: a potential source of artifacts in photoconductivity studies

The emission of electrons from conjugated polymer films occurs on laser photoexcitation at relatively low photon energies, <4 eV, and light intensities, <1015 photons/cm2 in a ca. 5 ns pulse. The transient conductivity resulting from the highly mobile electrons in the gas phase depends on the nature and pressure of the gaseous environment and can dominate the intrinsic photoconductivity in the bulk of the polymer. The photoelectron contribution to the overall photoconductivity can be quenched by a gaseous environment of CO2+10% SF6 at atmospheric pressure.