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Title
Rigidity-Induced Delayed Fluorescence by Ortho Donor-Appended Triarylboron Compounds: Record-High Efficiency in Pure Blue Fluorescent Organic Light-Emitting Diodes
Author(s)
이영훈이민형박성희신종원오지훈유성협정재훈
Publication Year
2017-07-19
Abstract
A synthetic approach to highly efficient thermally activated delayed fluorescence (TADF) is proposed that uses ortho donor (D)−acceptor (A) compounds (PXZoB, DPAoB, and CzoB), wherein the acceptor is based on triarylboron and the donor is phenoxazine (PXZ), diphenylamine (DPA), or carbazole (Cz). Combined with the ortho D−A connectivity, the bulky nature of the triarylboron endows the D−A dyads with inherent steric “locking” for a highly twisted arrangement, leading to a small energy difference between singlet and triplet excited states (ΔEST) and thus exhibiting very efficient TADF with microsecond-range lifetimes. In sharp contrast, the corresponding para D−A derivatives, DPApB and CzpB, only display short-lived, normal fluorescence. Organic light-emitting diodes (OLEDs) incorporating the proposed ortho D−A compounds as emitters display orange, greenish-blue, and pure blue emission and exhibit high external quantum efficiency (ηEQE). In particular, the pure blue OLEDs based on the proposed ortho D−A emitters with a carbazole donor (CzoB) show a record-high ηEQE of 22.6% with CIE color coordinates of (0.139, 0.150), well illustrating the validity of the proposed approach. Upon optical optimization, the ηEQE is further improved to 24.1%.
Journal Title
ACS Applied Materials & Interfaces
ISSN
1944-8244
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7. KISTI 연구성과 > 학술지 발표논문
URI
https://repository.kisti.re.kr/handle/10580/14650
http://www.ndsl.kr/ndsl/search/detail/article/articleSearchResultDetail.do?cn=NART78220722
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