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 pho toexcitation at relatively low photon energies, <4 eV, and light intensitie s, <10(15) photons/cm(2) in a ca. 5 ns pulse. The transient conductivity re sulting from the highly mobile electrons in the gas phase depends on the na ture and pressure of the gaseous environment and can dominate the intrinsic photoconductivity in the bulk of the polymer. The photoelectron contributi on to the overall photoconductivity can be quenched by a gaseous environmen t of CO2 + 10% SF6 at atmospheric pressure. (C) 2000 Elsevier Science B.V. All rights reserved.