am9b02824_si_001.pdf (1.72 MB)
Isomeric Quinoxalinedicarbonitrile as Color-Managing Acceptors of Thermally Activated Delayed Fluorescent Emitters
journal contribution
posted on 2019-04-22, 00:00 authored by Shantaram Kothavale, Kyung Hyung Lee, Jun Yeob LeeHighly
efficient yellow and red thermally activated delayed fluorescent (TADF)
organic light-emitting diodes were developed using two quinoxalinedicarbonitrile
units, quinoxaline-6,7-dicarbonitrile (6,7-DCQx) and quinoxaline-5,8-dicarbonitrile
(5,8-DCQx) as electron acceptors, and t-butylcarbazole
or 9,9-dimethylacridan as electron donors. The strong electron-withdrawing
capability of the 5,8-DCQx and 6,7-DCQx acceptors enabled from yellow
to red emission in the TADF emitters. Comparing 5,8-DCQx and 6,7-DCQx,
a red-shifted emission by about 40 nm was observed in the 5,8-DCQx
acceptor-based emitters, but the external quantum efficiency of the
TADF devices was over 20% irrespective of the acceptor, proving the
usefulness of the two acceptor moieties as the building blocks of
the TADF emitters. Therefore, the quinoxalinedicarbonitrile acceptors
are promising as the acceptor moiety for designing yellow or red TADF
emitters.