The effect of molecular structure on the efficiency of 1, 4-diazine–based D–(π)–A push-pull systems for non-doped OLED applications. (March 2021)

• Record Type: Journal Article
• Authors: Verbitskiy, Egor V.; Kvashnin, Yuriy A.; Bogdanov, Pavel I.; Medvedeva, Margarita V.; Svalova, Tatyana S.; Kozitsina, Alisa N.; Samsonova, Lubov G.; Degtyarenko, Konstantin M.; Grigoryev, Denis V.; Kurtcevich, Alexander E.; Gadirov, Ruslan M.; Rusinov, Gennady L.; Chupakhin, Oleg N.; Charushin, Valery N.
• Is Part Of: Dyes and pigments. Volume 187(2021)
• Publication Date: 2021-03
• Subjects: Pyrazine -- Quinoxaline -- OLEDs -- Organic emitter; Dyes and dyeing -- Periodicals; Pigments -- Periodicals; 667.2
• DOI: 10.1016/j.dyepig.2020.109124
• Languages: English
• ISSNs: 0143-7208

Abstract

Abstract: A series of novel D–A and D–π–A push-pull systems based on a pyrazine and quinoxaline acceptor, bearing various electron-donating triphenylamine and carbazole moieties, are compared. A significant difference in electrochemical and photophysical properties was found depending on molecular structure. The compounds have strong solvatochromic properties. Quinoxaline-containing systems exhibit delayed fluorescence (DF) in thermal vacuum deposition films. Despite the low quantum yield of fluorescence in the solid state (less than 10%), organic light-emitting diodes with sufficiently high efficiency (4.2 cd/A) have been fabricated on the basis of this push-pull systems. The best results were obtained for compounds exhibiting DF. The possible channel for increasing the efficiency of OLED can be associated with the "hot excitons" mechanism. Graphical abstract: Image 1 Highlights: 1, 4-Diazine-based D–(π)–A emitters were synthesized and investigated. Non-doped OLEDs achieved maximum current efficiency up to 4.2 cd/A. Yellow OLEDs demonstrating maximum brightness up to 3.2 × 10 4 cd/m 2 .