title: Interfacial widths of conjugated polymer bilayers.
abstract: The interfaces of conjugated polyelectrolyte (CPE)/poly[2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene] (MEH-PPV) bilayers cast from differential solvents are shown by resonant soft X-ray reflectivity (RSoXR) to be very smooth and sharp. The chemical interdiffusion due to casting is limited to less than 0.6 nm, and the interface created is thus nearly "molecularly" sharp. These results demonstrate for the first time and with high precision that the nonpolar MEH-PPV layer is not much disturbed by casting the CPE layer from a polar solvent. A baseline is established for understanding the role of interfacial structure in determining the performance of CPE-based polymer light-emitting diodes. More broadly, we anticipate further applications of RSoXR as an important tool in achieving a deeper understanding of other multilayer organic optoelectronic devices, including multilayer photovoltaic devices.
authors.affiliation: Department of Physics, North Carolina State University, Raleigh, North Carolina 27695, USA.
authors.forename: Cheng
authors.initials: C
authors.lastname: Wang
authors.forename: Andres
authors.initials: A
authors.lastname: Garcia
authors.forename: Hongping
authors.initials: H
authors.lastname: Yan
authors.forename: Karen E
authors.initials: KE
authors.lastname: Sohn
authors.forename: Alexander
authors.initials: A
authors.lastname: Hexemer
authors.forename: Thuc-Quyen
authors.initials: TQ
authors.lastname: Nguyen
authors.forename: Guillermo C
authors.initials: GC
authors.lastname: Bazan
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Kramer
authors.forename: Harald
authors.initials: H
authors.lastname: Ade