High-Efficiency Emissive Dendritic Phosphorescent Iridium (Iii) Complex with Thermally Activated Delayed Fluorescence Molecules as Functional Light-Harvesting Moieties

30 Pages Posted: 1 Sep 2022

See all articles by Yuchao Liu

Yuchao Liu

Qingdao University of Science and Technology

Yanchao Xie

Qingdao University of Science and Technology

Yannan Cheng

Beijing University of Chemical Technology

Xi Tian

Beijing University of Chemical Technology

Lei Hua

Beijing University of Chemical Technology

Shian Ying

Qingdao University of Science and Technology

Shouke Yan

Qingdao University of Science and Technology

Zhongjie Ren

affiliation not provided to SSRN

Abstract

Phosphorescent Iridium (III) complexes are considered as competitive candidates for fabricating efficient and stable display and illumination devices by the virtue of excellent exciton utilization. Nevertheless, the high-efficiency phosphorescent emitters available for solution-processable fabrication, are still deemed unsatisfactory for the mainstream industries. In this context, a valid strategy of linking thermally activated delayed fluorescence (TADF) group covalently to phosphorescent Iridium (III) complexes was proposed, in which TADF groups function as light-harvesting entities. In this way, the TADF units within the prepared complex TriTADF-Ir(dFppy)3, can effectively transfer energy to the phosphor core and thus boost device performances and reduce efficiency roll-off via alleviating the triplet exciton annihilations. As a result, the photoluminescence quantum yield of TriTADF-Ir(dFppy)3 blend film can reach to nearly 73%. Thanks to the peripheral TADF dendrons, flexible TriTADF-Ir(dFppy)3 can be employed in fabricating solution-processed phosphorescent organic light emitting diodes (PhOLEDs) with greenish-blue emission, which achieve external quantum efficiency (EQE) value over 20% and maintaining around 16% at 1000 cd/m2. Overall, this result manifests that the effective utilization of triplet excitons and consequently enhanced device performance of solution-processed PhOLEDs can be accomplished by utilizing TADF molecules as peripheral light-harvesting moieties to construct dendritic phosphorescent emitters.

Keywords: dendritic phosphorescent emitter, thermally activated delayed fluorescence (TADF), light-harvesting functional groups, solution-processed phosphorescent organic light emitting diodes (PhOLEDs), suppressed efficiency roll-off

Suggested Citation

Liu, Yuchao and Xie, Yanchao and Cheng, Yannan and Tian, Xi and Hua, Lei and Ying, Shian and Yan, Shouke and Ren, Zhongjie, High-Efficiency Emissive Dendritic Phosphorescent Iridium (Iii) Complex with Thermally Activated Delayed Fluorescence Molecules as Functional Light-Harvesting Moieties. Available at SSRN: https://ssrn.com/abstract=4206610 or http://dx.doi.org/10.2139/ssrn.4206610

Yuchao Liu

Qingdao University of Science and Technology ( email )

Qingdao, 266042
China

Yanchao Xie

Qingdao University of Science and Technology ( email )

Qingdao, 266042
China

Yannan Cheng

Beijing University of Chemical Technology ( email )

15 N. 3rd Ring Rd E
Chaoyang, Beijing, 201204
China

Xi Tian

Beijing University of Chemical Technology ( email )

15 N. 3rd Ring Rd E
Chaoyang, Beijing, 201204
China

Lei Hua

Beijing University of Chemical Technology ( email )

15 N. 3rd Ring Rd E
Chaoyang, Beijing, 201204
China

Shian Ying

Qingdao University of Science and Technology ( email )

Qingdao, 266042
China

Shouke Yan

Qingdao University of Science and Technology ( email )

Qingdao, 266042
China

Zhongjie Ren (Contact Author)

affiliation not provided to SSRN ( email )

No Address Available

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