| Title: |
Molecular Design Strategies for Color Tuning of Blue TADF Emitters. |
| Authors: |
Stachelek, P; Ward, JS; Dos Santos, PL; Danos, A; Colella, M; Haase, N; Raynes, SJ; Batsanov, AS; Bryce, MR; Monkman, AP |
| Publisher Information: |
American Chemical Society |
| Publication Year: |
2019 |
| Collection: |
Queen Mary University of London: Queen Mary Research Online (QMRO) |
| Subject Terms: |
TADF; blue OLEDs; charge transfer; donor/acceptor tuning; photophysics |
| Description: |
New thermally activated delayed fluorescence (TADF) blue emitter molecules based on the known donor-acceptor-donor (D-A-D)-type TADF molecule, 2,7-bis(9,9-dimethylacridin-10-yl)-9,9-dimethylthioxanthene-S,S-dioxide (DDMA-TXO2), are reported. The motivation for the present investigation is via the use of rational molecular design, based on DDMA-TXO2, to elevate the organic light emitting diode (OLED) performance and obtain deeper blue color coordinates. To achieve this goal, the strength of the donor (D) unit and acceptor (A) units have been tuned with methyl substituents. The methyl functionality on the acceptor was also expected to modulate the D-A torsion angle in order to obtain a blue shift in the electroluminescence. The effect of regioisomeric structures has also been investigated. Herein, we report the photophysical, electrochemical, and single-crystal X-ray crystallography data to assist with the successful OLED design. The methyl substituents on the DDMA-TXO2 framework have profound effects on the photophysics and color coordinates of the emitters. The weak electron-donating methyl groups alter the redox properties of the D and A units and consequently affect the singlet and triplet levels but not the energy gap (ΔEST). By systematically manipulating all of the aforementioned factors, devices have been obtained with acceptor-substituted III with a maximum external quantum efficiency of 22.6% and Commission Internationale de l'Éclairage coordinates of (0.15, 0.18) at 1000 cd m-2. |
| Document Type: |
article in journal/newspaper |
| File Description: |
27125 - 27133 |
| Language: |
English |
| Relation: |
ACS Appl Mater Interfaces; https://qmro.qmul.ac.uk/xmlui/handle/123456789/102547 |
| DOI: |
10.1021/acsami.9b06364 |
| Availability: |
https://qmro.qmul.ac.uk/xmlui/handle/123456789/102547; https://doi.org/10.1021/acsami.9b06364 |
| Rights: |
This is an open access article published under a Creative Commons Attribution (CC-BY)License, which permits unrestricted use, distribution and reproduction in any medium,provided the author and source are cited. ; © 2019 American Chemical Society |
| Accession Number: |
edsbas.2F9133B3 |
| Database: |
BASE |