Impact of the electrode material on the performance of light-emitting electrochemical cells

Fuente: arXiv
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Main Authors: Kirch, Anton, Park, So-Ra, Ràfols-Ribé, Joan, Kassel, Johannes A., Zhang, Xiaoying, Tang, Shi, Larsen, Christian, Edman, Ludvig
Format: Preprint
Published: 2024
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_version_ 1866916445033594880
author Kirch, Anton
Park, So-Ra
Ràfols-Ribé, Joan
Kassel, Johannes A.
Zhang, Xiaoying
Tang, Shi
Larsen, Christian
Edman, Ludvig
author_facet Kirch, Anton
Park, So-Ra
Ràfols-Ribé, Joan
Kassel, Johannes A.
Zhang, Xiaoying
Tang, Shi
Larsen, Christian
Edman, Ludvig
contents Light-emitting electrochemical cells (LECs) are promising candidates for fully solution-processed lighting applications because they can comprise a single active-material layer and air-stable electrodes. While their performance is often claimed to be independent of the electrode material selection due to the in-situ formation of electric double layers (EDLs), we demonstrate conceptually and experimentally that this understanding needs to be modified. Specifically, the exciton generation zone is observed to be affected by the electrode work function. We rationalize this finding by proposing that the ion concentration in the injection-facilitating EDLs depends on the offset between the electrode work function and the respective semiconductor orbital, which in turn influences the number of ions available for electrochemical doping and hence shifts the exciton generation zone. Further, we investigate the effects of the electrode selection on exciton losses to surface plasmon polaritons and discuss the impact of cavity effects on the exciton density. We conclude by showing that the measured electrode-dependent LEC luminance transients can be replicated by an optical model that considers these electrode-dependent effects to calculate the attained light outcoupling of the LEC stack. As such, our findings provide rational design criteria considering the electrode materials, the active-material thickness, and its composition in concert to achieve optimum LEC performance.
format Preprint
id arxiv_https___arxiv_org_abs_2410_14465
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Impact of the electrode material on the performance of light-emitting electrochemical cells
Kirch, Anton
Park, So-Ra
Ràfols-Ribé, Joan
Kassel, Johannes A.
Zhang, Xiaoying
Tang, Shi
Larsen, Christian
Edman, Ludvig
Optics
Soft Condensed Matter
Light-emitting electrochemical cells (LECs) are promising candidates for fully solution-processed lighting applications because they can comprise a single active-material layer and air-stable electrodes. While their performance is often claimed to be independent of the electrode material selection due to the in-situ formation of electric double layers (EDLs), we demonstrate conceptually and experimentally that this understanding needs to be modified. Specifically, the exciton generation zone is observed to be affected by the electrode work function. We rationalize this finding by proposing that the ion concentration in the injection-facilitating EDLs depends on the offset between the electrode work function and the respective semiconductor orbital, which in turn influences the number of ions available for electrochemical doping and hence shifts the exciton generation zone. Further, we investigate the effects of the electrode selection on exciton losses to surface plasmon polaritons and discuss the impact of cavity effects on the exciton density. We conclude by showing that the measured electrode-dependent LEC luminance transients can be replicated by an optical model that considers these electrode-dependent effects to calculate the attained light outcoupling of the LEC stack. As such, our findings provide rational design criteria considering the electrode materials, the active-material thickness, and its composition in concert to achieve optimum LEC performance.
title Impact of the electrode material on the performance of light-emitting electrochemical cells
topic Optics
Soft Condensed Matter
url https://arxiv.org/abs/2410.14465