Conjugated Polyelectrolytes Bearing Various Ion Densities: Spontaneous Dipole Generation, Poling-Induced Dipole Alignment, and Interfacial Energy Barrier Control for Optoelectronic Device Applications

Seungjin Lee, Thanh Luan Nguyen, Sang Yun Lee, Chung Hyeon Jang, Bo Ram Lee, Eui Dae Jung, Song Yi Park, Yung Jin Yoon, Jin Young Kim, Han Young Woo, Myoung Hoon Song

    Research output: Contribution to journalArticlepeer-review

    17 Citations (Scopus)

    Abstract

    Conjugated polyelectrolytes (CPEs) with π-delocalized main backbones and ionic pendant groups are intensively studied as interfacial layers for efficient polymer-based optoelectronic devices (POEDs) because they facilitate facile control of charge injection/extraction barriers. Here, a simple and effective method of performing precise interfacial energy level adjustment is presented by employing CPEs with different thicknesses and various ion densities under electric poling to realize efficient charge injection/extraction of POEDs. The effects of the CPE ion densities and electric (positive or negative) poling on the energy level tuning process are investigated by measuring the open-circuit voltages and current densities of devices with the structure indium tin oxide/zinc oxide/CPE/organic active layer/molybdenum oxide/gold while changing the CPE film thickness. The performances of inverted polymer light-emitting diodes and inverted polymer solar cells are remarkably improved by precisely controlling the interfacial energy level matching using optimum CPE conditions.

    Original languageEnglish
    Article number1706034
    JournalAdvanced Materials
    Volume30
    Issue number14
    DOIs
    Publication statusPublished - 2018 Apr 5

    Bibliographical note

    Funding Information:
    S.L. and T.L.N. contributed equally to this work. This work was supported by the National Research Foundation (NRF) of Korea (NRF-2016M1A2A2940911, 2012M3A6A7055540). This work was financially supported by the KIST-UNIST partnership program (1.160097.01/2.160482.01) and Mid-Career Research Program (2015R1A2A2A01003263).

    Publisher Copyright:
    © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

    Keywords

    • charge injection/extraction
    • conjugated polyelectrolytes (CPEs)
    • electric poling
    • ion density
    • polymer optoelectronic devices (POEDs)

    ASJC Scopus subject areas

    • General Materials Science
    • Mechanics of Materials
    • Mechanical Engineering

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