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Xu J, Sandström A, Lindh EM, Yang W, Tang S, Edman L. Challenging Conventional Wisdom: Finding High-Performance Electrodes for Light-Emitting Electrochemical Cells. ACS APPLIED MATERIALS & INTERFACES 2018; 10:33380-33389. [PMID: 30199215 DOI: 10.1021/acsami.8b13036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The light-emitting electrochemical cell (LEC) exhibits capacity for efficient charge injection from two air-stable electrodes into a single-layer active material, which is commonly interpreted as implying that the LEC operation is independent of the electrode selection. Here, we demonstrate that this is far from the truth and that the electrode selection instead has a strong influence on the LEC performance. We systematically investigate 13 different materials for the positive anode and negative cathode in a common LEC configuration with the conjugated polymer Super Yellow as the electroactive emitter and find that Ca, Mn, Ag, Al, Cu, indium tin oxide (ITO), and Au function as the LEC cathode, whereas ITO and Ni can operate as the LEC anode. Importantly, we demonstrate that the electrochemical stability of the electrode is paramount and that particularly electrochemical oxidation of the anode can prohibit the functional LEC operation. We finally report that it appears preferable to design the device so that the heights of the injection barriers at the two electrode/active material interfaces are balanced in order to mitigate electrode-induced quenching of the light emission. As such, this study has expanded the set of air-stable electrode materials available for functional LEC operation and also established a procedure for the evaluation and design of future efficient electrode materials.
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Affiliation(s)
- Jin Xu
- The Organic Photonics and Electronics Group, Department of Physics , Umeå University , SE-90187 Umeå , Sweden
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , China
- School of Mechanical Engineering , Dongguan University of Technology , Dongguan 523808 , China
| | - Andreas Sandström
- The Organic Photonics and Electronics Group, Department of Physics , Umeå University , SE-90187 Umeå , Sweden
- LunaLEC AB, Linnaeus Väg 24 , SE-901 87 Umeå , Sweden
| | - E Mattias Lindh
- The Organic Photonics and Electronics Group, Department of Physics , Umeå University , SE-90187 Umeå , Sweden
| | - Wei Yang
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , China
| | - Shi Tang
- The Organic Photonics and Electronics Group, Department of Physics , Umeå University , SE-90187 Umeå , Sweden
- LunaLEC AB, Linnaeus Väg 24 , SE-901 87 Umeå , Sweden
| | - Ludvig Edman
- The Organic Photonics and Electronics Group, Department of Physics , Umeå University , SE-90187 Umeå , Sweden
- LunaLEC AB, Linnaeus Väg 24 , SE-901 87 Umeå , Sweden
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