Issue 32, 2016

A highly twisted triarylborane-based biphenyl as an efficient host for blue and green phosphorescent OLEDs

Abstract

We report herein a novel triarylborane-based biphenyl derivative, o,o′-NPh2, which contains dimesitylboryl and diphenylamino groups at the lateral o,o′-positions of the biphenyl skeleton. This triarylborane-based biphenyl exhibits a high triplet energy (ET = 2.57 eV), which is much higher than its normal linear regioisomer, p,p′-NPh2 (ET = 2.28 eV), although their fluorescence spectra and thus singlet energies are very close. The high ET of o,o′-NPh2 is probably ascribed to its almost orthogonal conformation of the biphenyl skeleton, which would likely lead to good separation of the HOMO and LUMO and thus a small energy gap between the singlet and triplet excited states (ΔEST). The high ET of o,o′-NPh2 has allowed incorporation of it as a host material in blue and green phosphorescent OLEDs. The devices hosted by o,o′-NPh2 can achieve high performances with maximum external quantum efficiencies (EQEs), current efficiencies (CEs) and power efficiencies (PEs) of 15.3% and 22.2%, 34.5 cd A−1 and 84.2 cd A−1, 31.4 lm W−1 and 76.6 lm W−1 for blue and green phosphorescent OLEDs, respectively. Moreover, the green phosphorescent OLED has extremely low efficiency roll off. The EQE remains almost unchanged at 1000 cd m−2 and decreases by only 2.6% even at 10 000 cd m−2.

Graphical abstract: A highly twisted triarylborane-based biphenyl as an efficient host for blue and green phosphorescent OLEDs

Supplementary files

Article information

Article type
Paper
Submitted
14 Jun 2016
Accepted
17 Jul 2016
First published
19 Jul 2016

J. Mater. Chem. C, 2016,4, 7607-7613

A highly twisted triarylborane-based biphenyl as an efficient host for blue and green phosphorescent OLEDs

C. Wang, Y. Yuan, S. Li, Z. Sun, Z. Jiang and C. Zhao, J. Mater. Chem. C, 2016, 4, 7607 DOI: 10.1039/C6TC02451C

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