Pyridyl pyrrolide boron complexes: A new framework for facile generation of thermally activated delayed fluorescence and fabrication of organic light-emitting diodes
Journal
Angewandte Chemie International Edition
Journal Volume
55
Journal Issue
9
Pages
218-226
Date Issued
2016
Author(s)
Yi-Jiun Shiu
Yun-Chen Cheng
Wei-Lung Tsai
Chung-Chih Wu
Chun-Tien Chao
Yun Chi
Yi-Ting Chen
Shih-Hung Liu
Pi-Tai Chou
Abstract
The electron positive boron atom usually does not contribute to the frontier orbitals for several lower-lying electronic transitions, and thus is ideal to serve as a hub for the spiro linker of light-emitting molecules, such that the electron donor (HOMO) and acceptor (LUMO) moieties can be spatially separated with orthogonal orientation. On this basis, we prepared a series of novel boron complexes bearing electron deficient pyridyl pyrrolide and electron donating phenylcarbazolyl fragments or triphenylamine. The new boron complexes show strong solvent-polarity dependent charge-transfer emission accompanied by a small, non-negligible normal emission. The slim orbital overlap between HOMO and LUMO and hence the lack of electron correlation lead to a significant reduction of the energy gap between the lowest lying singlet and triplet excited states (ΔET-S ) and thereby the generation of thermally activated delay fluorescence (TADF).
SDGs
Type
journal article