| Donor-Acceptor Molecular Materials as Emitters and Hosts for Organic Light Emitting Diodes Ramin Pashzadeh1; Eigirdas Skuodis1; Ausra Tomkeviciene1; Dmytro Volyniuk1; Jurate Simokaitiene1; Egle Jatautiene1; Ramunas Lygaitis1; Juozas Vidas Grazulevicius1; 1KAUNAS UNIVERSITY OF TECHNOLOGY, Kaunas, Lithuania; PAPER: 83/AdvancedMaterials/Regular (Oral) SCHEDULED: 12:35/Sat. 26 Oct. 2019/Leda (99/Mezz. F) ABSTRACT: Molecular materials containing donor and acceptor moieties recently synthesized at the laboratories of the presenting author, and applied in organic light emitting diodes (OLEDs) as emitters and hosts will be reported. The derivative of 3-(trifluoromethyl)benzonitrile and 3,3' -bicarbazole was found to exhibit both delayed fluorescence and exciplex-forming properties [1]. Warm-white OLED based on this material showed external quantum efficiency (EQE) of ca. 20 %. The derivative of acridan and dicyanobenzene was found to be an efficient emitter, exhibiting both thermally activated delayed fluorescence (TADF) and aggregation induced emission enhancement. Green OLED fabricated using this emitter exhibited maximum current, power efficiency and EQE of 68 cd/m<sup>2</sup>, 62 lm/W and 22.5 %, respectively [2]. A series of carbazole-quinoxaline-carbazole derivatives exhibiting TADF and mechanochromic luminescence properties were synthesized and studied. Green-blue to green-yellow TADF OLEDs fabricated by solution processing demonstrated EQE up to 10.9% and luminance of 16760 cd m<sup>-2</sup> [3]. Deep-blue OLED based on triplet-triplet annihilation with EQE of 14.1% was fabricated [4]. This was done by utilization of the derivatives cyanophenyl and ditertbutylcarbazolyl which were substituted with triphenylbenzene and different substitution patterns as hosts and guests of the emissive layer. This research was funded by the European Social Fund according to the activity "Improvement of researchers" qualification by implementing world-class R&D projects of Measure No. 09.3.3-LMT-K-712. References: [1] G. Grybauskaite-Kaminskiene et al. J. Mater. Chem. C, 6 (2018) 1543. [2] Skuodis E. et al. Org. Electron., 63 (2018)29 (2018). [3] Pashazadeh R. et al. J. Phys. Chem. Lett., 9 (2018) 1172. [4] Kukhta N. et al. J. Phys. Chem. Lett.2017, 8 (2017) 6199. |
