Rational design of perfectly oriented thermally activated delayed fluorescence emitter for efficient red electroluminescence [具有完美水平取向的?光型?活化延??光材料]
Journal
Science China Materials
Journal Volume
64
Journal Issue
4
Pages
920-930
Date Issued
2021
Author(s)
Zeng X
Abstract
How to control the dipole orientation of organic emitters is a challenge in the field of organic light-emitting diodes (OLEDs). Herein, a linear thermally activated delayed fluorescence (TADF) molecule, PhNAI-PMSBA, bearing a 1,8-naphthalimide-acridine framework was designed by a double-site long-axis extension strategy to actively control the dipole orientation. The horizontal ratio of emitting dipole orientation of PhNAI-PMSBA reaches 95%, substantially higher than that of isotropic emitters (67%). This unique feature is associated with the intrinsically horizontal molecular orientation of PhNAI-PMSBA and the good agreement between its transition dipole moment direction and molecular long axis. The PhNAI-PMSBA-based OLED achieves an ultrahigh optical outcoupling efficiency of 43.2% and thus affords one of the highest red electroluminescence with an external quantum efficiency of 22.3% and the Commission International de l’Eclairage 1931 coordinates at around (0.60, 0.40). ? 2020, Science China Press and Springer-Verlag GmbH Germany, part of Springer Nature.
Subjects
Efficiency; Fluorescence; Molecular orientation; Organic light emitting diodes (OLED); Dipole orientation; External quantum efficiency; Organic emitters; Organic light emitting diodes(OLEDs); Out-coupling efficiency; Red electroluminescence; Thermally activated delayed fluorescences; Transition dipole moments; Electroluminescence
SDGs
Type
journal article