title: Phase-separated thin film structures for efficient polymer blend light-emitting diodes.
abstract: We report laterally and vertically phase-separated thin film structures in conjugated polymer blends created by polymer molecular weight variation. We find that micrometer-scale lateral phase separation is critical in achieving high initial device efficiency of light-emitting diodes, whereas improved balance of charge carrier mobilities and film thickness uniformity are important in maintaining high efficiency at high voltages. The optoelectronic properties of these blend thin films and devices are strongly influenced by the polymer chain order/disorder and the interface state formed at polymer/polymer heterojunctions.
authors.affiliation: Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, UK.
authors.forename: Keng-Hoong
authors.initials: KH
authors.lastname: Yim
authors.forename: Walter J
authors.initials: WJ
authors.lastname: Doherty
authors.forename: William R
authors.initials: WR
authors.lastname: Salaneck
authors.forename: Craig E
authors.initials: CE
authors.lastname: Murphy
authors.forename: Richard H
authors.initials: RH
authors.lastname: Friend
authors.forename: Ji-Seon
authors.initials: JS
authors.lastname: Kim