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Jin P, Zhou Z, Wang H, Hao J, Chen R, Wang J, Zhang C. Spin-Enhanced Reverse Intersystem Crossing and Electroluminescence in Copper Acetate-Doped Thermally Activated Delayed Fluorescence Material. J Phys Chem Lett 2022; 13:2516-2522. [PMID: 35275641 DOI: 10.1021/acs.jpclett.2c00300] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Thermally activated delayed fluorescence (TADF) materials are attractive for next-generation organic light-emitting diodes (OLEDs) because of their utilization of nonradiative triplets via reverse intersystem crossing (RISC), which requires not only a small singlet-triplet energy splitting but also the conservation of spin angular momentum. Here we use copper acetate as a spin sensitizer to facilitate RISC and thus enhance electroluminescence in TADF-exciplex OLEDs. Copper acetate is involved in the radiative decay process due to its coordination interaction with exciplex molecules having intermolecular charge-transfer characteristics, which causes significant changes in the photoluminescence intensity and lifetime. Meanwhile, magneto-photoluminescence reveals that the addition of copper acetate promotes spin conversion in the RISC process. It allows the enhancement of the electroluminescence (∼80%) from spin-sensitized OLEDs, accompanied by the suppression of magneto-electroluminescence upon the doping of copper acetate. These results illustrate that using a spin sensitizer may overcome the limitation of harvesting nonradiative triplets in organic luminescent materials and devices.
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Affiliation(s)
- Pengfei Jin
- Key Laboratory of Photochemistry, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zeyang Zhou
- Key Laboratory of Photochemistry, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hong Wang
- Key Laboratory of Photochemistry, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jinjie Hao
- Key Laboratory of Photochemistry, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Rui Chen
- Key Laboratory of Photochemistry, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jingying Wang
- School of Physics, Sun Yat-sen University, Guangzhou 510275, China
| | - Chuang Zhang
- Key Laboratory of Photochemistry, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
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