120th General Meeting of the KCS

Type Poster Presentation
Area Inorganic Chemistry
Room No. Exhibition Hall 2+3
Time 10월 19일 (목요일) 11:00~12:30
Code INOR.P-8
Subject Ortho Donor-Appended Triarylboron Emitters for Record-High Efficiency in Pure Blue TADF Organic Light-Emitting Diodes
Authors Young Hoon Lee, SURENDRAN SUJITH, HeeChai Lee, Jung Jaehoon, Min Hyung Lee*
Department of Chemistry, University of Ulsan, Korea
Abstract Highly efficient thermally-activated delayed fluorescence (TADF) is proposed using ortho donor (D)―acceptor (A) compounds (PXZoB, DPAoB, CzoB) wherein acceptor is based on triarylboron and 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 highly twisted arrangement, leading to a small energy difference between singlet and triplet excited states (△EST) 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) shows the 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, its ηEQE is further improved to 24.1%.
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