New Charge-Transfer Mechanism across the Interface between Selenium and Polystyrene Hexylmethacrylate

Thin-film structures composed of amorphous Se and polystyrene-hexylmethacrylate copolymer sandwiched between two semitransparent Al electrodes have been studied using transient photocurrent techniques. The dependence of the observed "transit time" on the applied voltage showed lengthening as the voltage was increased, contrary to the expected behavior in the time-of-flight experiments! This novel effect has been associated with a rate-limited charge-transfer mechanism across the Se-polymer interface.