2019-Sustainable Industrial Processing Summit
SIPS2019 Volume 11: New and Advanced Materials, Technologies, and Manufacturing
| Editors: | F. Kongoli, F. Marquis, N. Chikhradze, T. Prikhna |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2019 |
| Pages: | 174 pages |
| ISBN: | 978-1-989820-10-0 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
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Development of New Multicolor-Exciplex Emitters Utilizing Diphenylsulfone/Ditolylsulfone and Phenothiazine/Phenoxathiine/Xanthene Moieties for White Electroluminescent Devices
Dmytro Volyniuk1; Xiaofeng Tan1; Jurate Simokaitiene1; Audrius Bucinskas1; Tomas Matulaitis1; Egle Jatautiene1; Khrystyna Ivaniuk2; Igor Helzhynskyy2; Pavlo Stakhira2; Juozas Vidas Grazulevicius1;1KAUNAS UNIVERSITY OF TECHNOLOGY, Kaunas, Lithuania; 2LVIV POLYTECHNIC NATIONAL UNIVERSITY, Lviv, Ukraine;
Type of Paper: Regular
Id Paper: 88
Topic: 43
Abstract:
Exciplex-forming systems based on solid-state mixtures of electron donating and electron accepting compounds have a bright prospect to maximize the thermally activated delayed fluorescence (TADF) contribution. These systems can also achieve 100 % of theoretical internal quantum efficiency (IQE) of organic light-emitting devices (OLEDs) [1, 2]. Recently, a unique application of donor-acceptor (D-A) compounds as versatile exciplex-forming materials for simplified non-doped white organic light-emitting devices was proposed [3]. Maximum external quantum efficiency of these devices, however, did not exceed 3.15 %.
The aim of this study was to design versatile exciplex-forming materials with improved triplet energies, charge transport, and HOMO and LUMO energy levels. This is to allow for hole and electron injection required for highly efficient white electroluminescent devices, for phenoxathiine and xanthene as donors, and for six new D-A compounds based on diphenylsulfone and ditolylsulfone as acceptors and phenothiazines. To study the potential of these compounds as versatile exciplex-forming materials, their absorption, emission spectra, excited state lifetimes and singlet-triplet energy gaps were measured for characterization of photophysical propertie. Meanwhile, cyclic voltammetry, thermogravimetric analysis, as well as differential scanning calorimetry measurements were performed for probing of electrochemical and thermal properties. Photoelectron emission spectrometry was used for characterization of charge-injection properties of the studied compounds in their solid state. Time-of-flight measurements were used for estimation of charge-transporting properties. The results obtained are discussed with the support of theoretical calculations. Two compounds showed ability to form blue and orange exciplexes in solid-state mixtures with tris(4-carbazolyl-9-ylphenyl)amine or 4”-tris[phenyl(m-tolyl)amino]triphenylamine, respectively. For blue and orange monochromatic OLEDs prepared using the best TADF exciplex-forming materials, maximum external quantum efficiencies of 10% and 12% were achieved, respectively. An approach exploiting the structure of blue exciplex/spacer/orange exciplex was developed for white all-exciplex based electroluminescence, reaching maximum external quantum efficiency of 10 %. This research was funded by the European Regional Development Fund according to the supported activity "Research Projects Implemented by World-class Researcher Groups’ under Measure No. 01.2.2-LMT-K-718.
Keywords:
New and advanced materials; New and advanced technology;References:
[1] K. Goushi, K. Yoshida, K. Sato, C. Adachi, Nat. Photonics. 6 (4) (2012) 253-258.[2] M. Sarma, K.-T. Wong, ACS Appl. Mater. Interfaces. 10 (23) (2018) 19279-19304.
[3] G. Sych, D. Volyniuk, O. Bezvikonnyi, R. Lytvyn, J.V. Grazulevicius. J. Phys. Chem. C. 123 (2019) (4), 2386-2397.