Efficient Blue Polymer Light-Emitting Diodes with Electron-Dominated Transport Due to Trap Dilution

Davood Abbaszadeh, Paul W. M. Blom*

*Corresponding author for this work

    Research output: Contribution to journalArticleAcademicpeer-review

    10 Citations (Scopus)

    Abstract

    As is common for many conjugated polymers used in light-emitting diodes (PLEDs), the charge transport in blue-emitting polyspirobifluorene (PSF) copolymerized with the hole transport unit - N,N,N'N'-tetraaryldiamino (TAD) biphenyl - is dominated by holes. Although the free electron mobility is an order of magnitude higher than the hole mobility, the electron transport is strongly hindered by traps. By diluting PSF-TAD with the wide band gap polymer poly(9,9-di-n-octylfluorenyl-2,7-diyl) (PFO), the effect of electron trapping can be nearly eliminated. As a result, the transport in the PSF-TAD:PFO blend becomes electron dominated. Due to the higher electron mobility, PLEDs made from these blends exhibit higher current and light-output as compared to hole-dominated PLEDs made from pristine PSF-TAD. The reduced amount of electron traps enhances their efficiency from 2 cd A(-1) for the hole-dominated PLED to 5.3 cd A(-1) for the electron-dominated blend PLED.

    Original languageEnglish
    Article number1500406
    Number of pages6
    JournalAdvanced electronic materials
    Volume2
    Issue number7
    DOIs
    Publication statusPublished - Jul-2016

    Keywords

    • SEMICONDUCTING POLYMERS
    • HOLE-TRANSPORT
    • RECOMBINATION

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