Identifying Key Properties of Electrolytes for Light-Emitting Electrochemical Cells

The electrolyte is a key component in light-emitting electrochemical cells (LECs), as it facilitates in situ electrochemical doping and associated attractive device features. LiCF3SO3 dissolved in hydroxyl-capped trimethylolpropane ethoxylate (TMPE-OH) constitutes an electrolyte with which we have a...

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Bibliographic Details
Published inChemistry of materials Vol. 26; no. 17; pp. 5083 - 5088
Main Authors Tang, Shi, Mindemark, Jonas, Araujo, Carlos Moyses Graca, Brandell, Daniel, Edman, Ludvig
Format Journal Article
LanguageEnglish
Published American Chemical Society 09.09.2014
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Summary:The electrolyte is a key component in light-emitting electrochemical cells (LECs), as it facilitates in situ electrochemical doping and associated attractive device features. LiCF3SO3 dissolved in hydroxyl-capped trimethylolpropane ethoxylate (TMPE-OH) constitutes an electrolyte with which we have attained high stability and efficiency for polymer LECs, but the turn-on time of such devices is unfortunately slow. By replacing hydroxyl with methoxy as the TMPE end-group, we produced LECs with a desired combination of high efficiency, good stability, and fast turn-on time. Specifically, we showed that the turn-on time to high luminance (300 cd/m2) at a current density of 7.7 mA/cm2 is lowered from 1740 to 16 s, that the efficiency is improved by ∼20%, and that the other device properties are either maintained or improved. In a parallel modeling and experimental effort, we demonstrated that the faster kinetics following the shift in the TMPE end-group is attributed to a marked decrease in the level of both inter- and intramolecular interactions of the electrolyte, as manifested in a lowered electrolyte viscosity, faster ion transport, and more facile ion release during doping.
ISSN:0897-4756
1520-5002
1520-5002
DOI:10.1021/cm5022905