High-efficiency polymer LEDs with fast response times fabricated via selection of electron-injecting conjugated polyelectrolyte backbone structure

Minwon Suh, Jim Bailey, Sung Wook Kim, Kyungmok Kim, Dong Jin Yun, Youngsuk Jung, Iain Hamilton, Nathan Chander, Xuhua Wang, Donal D.C. Bradley, Duk Young Jeon, Ji Seon Kim

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Imidazolium ionic side-group-containing fluorene-based conjugated polyelectrolytes (CPEs) with different π-conjugated structures, poly[(9,9-bis(8′-(3-methyl-1-imidazolium)octyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] dibromide (F8im-Br) and poly[(9,9-bis(8′-(3-methyl-1-imidazolium)octyl)-2,7-fluorene)-alt-(benzo(2,1,3)thiadiazol-4,8-diyl) dibromide (F8imBT-Br), are synthesized and utilized as an electron injection layer (EIL) in green-emitting F8BT polymer light-emitting diodes (PLEDs). Both CPE EIL devices significantly outperform Ca cathode devices; 17.9 cd A-1 (at 3.8 V) and 16.6 lm W-1 (at 3.0 V) for F8imBT-Br devices, 11.1 cd A-1 (at 4.2 V) and 9.1 lm W-1 (at 3.4 V) for F8im-Br devices, and 7.2 cd A-1 (at 3.6 V) and 7.0 lm W-1 (at 3.0 V) for Ca devices. Importantly, unlike the F8im-Br EIL devices, F8imBT-Br PLEDs exhibit much faster electroluminescence turn-on times (
Original languageEnglish (US)
JournalACS Applied Materials and Interfaces
Issue number48
StatePublished - Dec 9 2015
Externally publishedYes

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