Kim, Hosub Cho, Jinhan Kim, Dong Young Char, Kookheon 2024-01-21T00:05:30Z 2024-01-21T00:05:30Z 2021-09-02 2007-11 0040-6090 https://pubs.kist.re.kr/handle/201004/133998 Multilayer films composed of poly(p-phenylene vinylene) (PPV) as the semiconducting polymer and poly(methacrylic acid) (PMAA) as the insulating polymer were fabricated by spin-assembly method. These films, comprising a confined layer structure, showed that the water contact angles are periodically and distinctly oscillated when the top surface layer is alternated between PPV precursor and PMAA. The turn-on voltage of the multilayer electroluminescent (EL) devices increased from 2.6 V to 9.8 V as the thickness of the PMAA layer inserted between neighboring PPV layers was increased from 0 (i.e., PPV single layer film) to 2.0 nm. Furthermore, the emission peaks in the photoluminescent and EL spectra of these devices were strongly blue-shifted due to excitons formed at the confined PPV layers. Particularly when inserting about 1.0 nm thick PMAA layers, which possibly induced a tunneling effect on the charge carriers (i.e., holes and electrons), these multilayer films decreased the mobility of the hole carriers in the PPV layers with strong hole transporting characteristics, and therefore increased the recombination probability in the emitting layer with confined geometry. As a result, the device efficiency was significantly improved in comparison with that of a PPV single layer device without PMAA layer and with that of devices with relatively thick PMAA layers of 1.4 or 2.0 nm. (C) 2007 Elsevier B.V. All rights reserved. English ELSEVIER SCIENCE SA Electroluminescent characteristics of spin-assembled multilayer films with confined layer structure Article 10.1016/j.tsf.2007.04.152 1 THIN SOLID FILMS, v.516, no.1, pp.78 - 83 THIN SOLID FILMS 516 1 78 83 N scie scopus 000250638800013 2-s2.0-34748829661 Materials Science, Multidisciplinary Materials Science, Coatings & Films Physics, Applied Physics, Condensed Matter Materials Science Physics Article LIGHT-EMITTING-DIODES SEQUENTIALLY ADSORBED MULTILAYERS MULTIPLE-QUANTUM-WELL THIN-FILMS POLYMER FABRICATION DEPOSITION EFFICIENCY DEVICES INTERFACE multilayer spin-assembly quantum confinement layer-by-layer