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Chen YS, Lin IH, Huang HY, Liu SW, Hung WY, Wong KT. Exciplex-forming cohost systems with 2,7-dicyanofluorene acceptors for high efficiency red and deep-red OLEDs. Sci Rep 2024; 14:2458. [PMID: 38291066 PMCID: PMC10827723 DOI: 10.1038/s41598-024-52680-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 01/21/2024] [Indexed: 02/01/2024] Open
Abstract
Two 2,7-dicyaonfluorene-based molecules 27-DCN and 27-tDCN are utilized as acceptors (A) to combine with hexaphenylbenzene-centered donors (D) TATT and DDT-HPB for probing the exciplex formation. The photophysical characteristics reveal that the steric hindered 27-tDCN not only can increase the distance of D and A, resulting in a hypsochromic emission, but also dilute the concentration of triplet excitons to suppress non-radiative process. The 27-tDCN-based exciplex-forming blends exhibit better photoluminescence quantum yield (PLQY) as compared to those of 27-DCN-based pairs. In consequence, among these D:A blends, the device employing DDT-HPB:27-tDCN blend as the emissiom layer (EML) exhibits the best EQE of 3.0% with electroluminescence (EL) λmax of 542 nm. To further utilize the exciton electrically generated in exciplex-forming system, two D-A-D-configurated fluorescence emitter DTPNT and DTPNBT are doped into the DDT-HPB:27-tDCN blend. The nice spectral overlap ensures fast and efficient Förster energy transfer (FRET) process between the exciplex-forming host and the fluorescent quests. The red device adopting DDT-HPB:27-tDCN:10 wt% DTPNT as the EML gives EL λmax of 660 nm and maximum external quantum efficiency (EQEmax) of 5.8%, while EL λmax of 685 nm and EQE of 5.0% for the EML of DDT-HPB:27-tDCN:10 wt% DTPNBT. This work manifests a potential strategy to achieve high efficiency red and deep red OLED devices by incorporating the highly fluorescent emitters to extract the excitons generated by the exciplex-forming blend with bulky acceptor for suppressing non-radiative process.
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Affiliation(s)
- Yi-Sheng Chen
- Organic Electronic Research Center, Ming Chi University of Technology, New Taipei City, 24031, Taiwan
- Department of Chemistry, National Taiwan University, Taipei, 10617, Taiwan
| | - I-Hung Lin
- Department of Optoelectronics and Materials Technology, National Taiwan Ocean University, Keelung, 20224, Taiwan
| | - Hsin-Yuan Huang
- Department of Optoelectronics and Materials Technology, National Taiwan Ocean University, Keelung, 20224, Taiwan
| | - Shun-Wei Liu
- Organic Electronic Research Center, Ming Chi University of Technology, New Taipei City, 24031, Taiwan
| | - Wen-Yi Hung
- Department of Optoelectronics and Materials Technology, National Taiwan Ocean University, Keelung, 20224, Taiwan.
| | - Ken-Tsung Wong
- Department of Chemistry, National Taiwan University, Taipei, 10617, Taiwan.
- Institute of Atomic and Molecular Science Academia Sinica, Taipei, 10617, Taiwan.
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