Hybrid White-Light-Emitting Electrochemical Cells Based on a Blue Cationic Iridium(III) Complex and Red Quantum Dots

Ya-Han Tang; Yi-Chan Chiu; Dian Luo; Jiun-Yi Lien; Rong-Huei Yi; Ching-Hsuan Lin; Zu-Po Yang; Chin-Wei Lu; Hai-Ching Su

doi:10.1002/chem.202001994

Hybrid White-Light-Emitting Electrochemical Cells Based on a Blue Cationic Iridium(III) Complex and Red Quantum Dots

Chemistry. 2020 Oct 27;26(60):13668-13676. doi: 10.1002/chem.202001994. Epub 2020 Sep 28.

Authors

Ya-Han Tang¹, Yi-Chan Chiu¹, Dian Luo¹, Jiun-Yi Lien², Rong-Huei Yi³, Ching-Hsuan Lin³, Zu-Po Yang⁴, Chin-Wei Lu³, Hai-Ching Su¹

Affiliations

¹ Institute of Lighting and Energy Photonics, National Chiao Tung University, Tainan, 71150, Taiwan.
² Center for Quantum Frontiers of Research & Technology (QFort), National Cheng Kung University, Tainan, 70101, Taiwan.
³ Department of Applied Chemistry, Providence University, Taichung, 43301, Taiwan.
⁴ Institute of Photonic System, National Chiao Tung University, Tainan, 71150, Taiwan.

PMID: 33463782
DOI: 10.1002/chem.202001994

Abstract

Solid-state white light-emitting electrochemical cells (LECs) show promising advantages of simple solution fabrication processes, low operation voltage, and compatibility with air-stable cathode metals, which are required for lighting applications. To date, white LECs based on ionic transition metal complexes (iTMCs) have shown higher device efficiencies than white LECs employing other types of materials. However, lower emission efficiencies of red iTMCs limit further improvement in device performance. As an alternative, efficient red CdZnSeS/ZnS core/shell quantum dots were integrated with a blue iTMC to form a hybrid white LEC in this work. By achieving good carrier balance in an appropriate device architecture, a peak external quantum efficiency and power efficiency of 11.2 % and 15.1 lm W^-1, respectively, were reached. Such device efficiency is indeed higher than those of the reported white LECs based on host-guest iTMCs. Time- and voltage-dependent electroluminescence (EL) characteristics of the hybrid white LECs were studied by means of the temporal evolution of the emission-zone position extracted by fitting the simulated and measured EL spectra. The working principle of the hybrid white LECs was clarified, and the high device efficiency makes potential new white-emitting devices suitable for solid-state lighting technology possible.

Keywords: electrochemistry; ionic transition metal complexes; iridium; light-emitting electrochemical cells; quantum dots.

Abstract

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