0000000000505645
AUTHOR
Oleksandr Bezvikonnyi
All-organic fast intersystem crossing assisted exciplexes exhibiting sub-microsecond thermally activated delayed fluorescence
A novel strategy is presented towards acquisition of exciplex systems exhibiting thermally activated delayed fluorescence (TADF) with a high reverse intersystem crossing (RISC) rate (exceeding 107 s−1). This approach involves constructing exciplex donor–acceptor molecular pairs, where the acceptor molecule possesses the ability to undergo fast and efficient intersystem crossing (ISC). With the use of 6-cyano-9-phenylpurine (PCP) acceptor and carbazole-based donor molecules, exciplexes were obtained, where the excitation is contained on PCP and undergoes fast ISC to form a local excited triplet state (3LEA). The controlled excitation transfer to the 3LEA level provides an optimal reverse int…
Pyrenyl substituted 1,8-naphthalimide as a new material for weak efficiency-roll-off red OLEDs: a theoretical and experimental study
Based on the theoretical calculations of excited states and semiconducting properties, a new 1,8-naphthalimide derivative having an electron-donating 1-pyrenyl group at the C-4 position was designed and synthesized. This derivative exhibited an excellent thermal stability and bipolar charge carrier transport ability. It was successfully utilized as a host in red phosphorescent organic light-emitting diodes showing an efficient energy transfer from the host to the phosphorescent emitter. The derivative may be a single material electroplex-forming host for PhOLEDs. The best fabricated red emitting device demonstrated maximum current, power, and external quantum efficiencies of 10.8 cd A−1, 7 …
Effect of donor substituents on thermally activated delayed fluorescence of diphenylsulfone derivatives
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. DG acknowledges to the ERDF PostDoc project No. 1.1.1.2/VIAA/1/16/177;
HAPPY Dyes as Light Amplification Media in Thin Films
A series of 1Hamorphous tri-phenyl pyridine (HAPPY) dyes have been synthesized from luminescent triphenyl-group-containing 2-methyl-6-styryl-substituted-4H-pyran-4-ylidene derivatives in reactions with benzylamine and investigated for suitability as solution-processable light-emitting medium components in thin films for amplified spontaneous emission (ASE). Conversion of a 4H-pyrane ring into a 1H-pyridine fragment enables aggregation-induced emission enhancement (AIEE) behavior in the target products and slightly increases thermal stability, glass transition temperatures, and ASE efficiency with PLQY up to 15% and ASE thresholds as low as 46 μJ/cm2 in neat spin-cast films, although thermal…
Differently substituted benzonitriles for non-doped OLEDs
DG acknowledges to the ERDF PostDoc grant No. 1.1.1.2/VIAA/1/16/177 . 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 .
Diphenylsulfone-based hosts for electroluminescent devices: Effect of donor substituents
DG acknowledges to the ERDF PostDoc project No. 1.1.1.2/VIAA/1/16/177. This work was supported by the project of scientific co-operation program between Latvia, Lithuania and Taiwan ?Polymeric Emitters with Controllable Thermally Activated Delayed Fluorescence for Solution-processable OLEDs? (grant No. S-LLT-19-4). Support of the Lithuanian Academy of Sciences is gratefully acknowledged; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART²
Flexible diphenylsulfone versus rigid dibenzothiophene-dioxide as acceptor moieties in donor-acceptor-donor TADF emitters for highly efficient OLEDs
DG acknowledges funding from the ERDF PostDoc project No. 1.1.1.2/VIAA/1/16/177 . This research is/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 . Ministry of Science and Technology (MOST), Taiwan , Grant No. MOST 106-2923-E-155-002-MY3 . This work was also supported by the Ministry of Education and Science of Ukraine (projects no. 0117U003908 and 0118U003862 ), and by the Olle Engkvist Byggmästare foundation (contract No. 189-0223 ). The quantum-chemical calculations were performed with computational resources provided by the High Performance Comp…
Methoxycarbazolyl-disubstituted dibenzofuranes as holes- and electrons-transporting hosts for phosphorescent and TADF-based OLEDs
This research was funded by European Social Fund (Project No 09.3.3-LMT-K-712-02-0105). DG acknowledges to the ERDF PostDoc grant No. 1.1.1.2/VIAA/1/16/177.
CCDC 1830576: Experimental Crystal Structure Determination
Related Article: Oleksandr Bezvikonnyi, Dalius Gudeika, Dmytro Volyniuk, Juozas V. Grazulevicius, Gintautas Bagdziunas|2018|New J.Chem.|42|12492|doi:10.1039/C8NJ01866A
CCDC 1988182: Experimental Crystal Structure Determination
Related Article: Kaspars Traskovskis, Armands Sebris, Irina Novosjolova, Māris Turks, Matas Guzauskas, Dmytro Volyniuk, Oleksandr Bezvikonnyi, Juozas V. Grazulevicius, Anatoly Mishnev, Raitis Grzibovskis, Aivars Vembris|2021|J.Mater.Chem.C|9|4532|doi:10.1039/D0TC05099G