Electroluminescent characteristics of spin-assembled multilayer films with confined layer structure

Hosub Kim, Jinhan Cho, Dong Young Kim, Kookheon Char

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)78-83
Number of pages6
JournalThin Solid Films
Volume516
Issue number1
DOIs
Publication statusPublished - 2007 Nov 1
Externally publishedYes

Fingerprint

Multilayer films
Acids
acids
Semiconducting polymers
Luminescent devices
Charge carriers
Excitons
Contact angle
methacrylic acid
Polymers
Multilayers
polymers
Geometry
Electrons
Water
Electric potential
charge carriers
surface layers
assembly
excitons

Keywords

  • Layer-by-layer
  • Multilayer
  • Quantum confinement
  • Spin-assembly

ASJC Scopus subject areas

  • Surfaces, Coatings and Films
  • Condensed Matter Physics
  • Surfaces and Interfaces

Cite this

Electroluminescent characteristics of spin-assembled multilayer films with confined layer structure. / Kim, Hosub; Cho, Jinhan; Kim, Dong Young; Char, Kookheon.

In: Thin Solid Films, Vol. 516, No. 1, 01.11.2007, p. 78-83.

Research output: Contribution to journalArticle

Kim, Hosub ; Cho, Jinhan ; Kim, Dong Young ; Char, Kookheon. / Electroluminescent characteristics of spin-assembled multilayer films with confined layer structure. In: Thin Solid Films. 2007 ; Vol. 516, No. 1. pp. 78-83.
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