Title
Molecular design of highly effective thermally activated delayed fluorescence emitters based on ortho-substituted donor-acceptor-donor pyridinecarbonitrile derivatives and their application for high-performance OLEDs
Author
Shin Hyung Choi, Chan Hee Lee, Chihaya Adachi, Sae Youn Lee
Year
2019
Journal
Dyes and Pigments
Abstract
In this work, we designed and investigated two TADF molecules, AcCN and PxCN, introducing donor moieties into the 3,5-position of 4-pyridinecarbonitrile acceptor core. These D‒A‒D type compounds exhibit effective utilization of triplet excitons through a reverse intersystem crossing (RISC) process with relatively small singlet-triplet energy splitting (ΔEST) values less than 0.1 eV. With their high PL quantum yield (ΦPL) and sufficient rate constant for RISC process (kRISC), organic light-emitting diodes (OLEDs) employing AcCN and PxCN as emitters achieve a maximum external quantum efficiency (ηext) of 20.6% and 15.5%, respectively, with green emissions.
Instrument
FP-8600
Keywords
Fluorescence, Photoluminescence, Optical properties, Materials