title: Enhanced performance of blue polymer light-emitting diodes by a self-assembled thin interlayer.
abstract: High efficiency and long lifetime, blue polymer light-emitting diodes were obtained by adding a thin interlayer, which was fabricated by a layer-by-layer self-assembly technique between poly(3,4-ethylene dioxythiophene)-poly(styrene sulfonic acid) (PEDOT:PSS) hole transporting and emissive polymer layers in the device configuration of indium tin oxide (ITO)/PEDOT:PSS (65 nm)/interlayer (10-30 nm)/emissive polymer (70 nm)/BaF2 (2 nm)/Ca (50 nm)/Al (300 nm). The interlayer, (PPV/PSS)n, consisted of self-assembled multilayers of the conjugated polymer, poly (p-phenylenevinylene) (PPV), and the polyelectrolyte, poly (styrene sulfonic acid) (PSS). Electroluminescence (EL) characteristics such as luminescence and current efficiency of the devices were enhanced by the addition of the interlayer. Furthermore, the devices with interlayer showed longer lifetime than those without interlayer. The maximum device performance was obtained from the device with (PPV/PSS)3 interlayer.
authors.affiliation: Department of Chemistry, Hanyang University, Haengdang-dong 17, Sungdong-ku, Seoul, 133-791, Korea.
authors.forename: Yun Ho
authors.initials: YH
authors.lastname: Kim
authors.forename: Wonjoo
authors.initials: W
authors.lastname: Lee
authors.forename: Gangri
authors.initials: G
authors.lastname: Cai
authors.forename: Su Jin
authors.initials: SJ
authors.lastname: Baek
authors.forename: Sung-Hwan
authors.initials: SH
authors.lastname: Han
authors.forename: Soo-Hyoung
authors.initials: SH
authors.lastname: Lee