Gadirov, Ruslan M.

Kurtcevich, A. E.

Samsonova, Lyubov G.

Verbitskiy, E. V.

English

Tomsk State University Repository

PULSED LASERS AND LASER APPLICATIONSTHE 15th  INTERNATIONAL CONFERENCEThe 15th International Conference AMPL-2021 PULSED LASERS AND LASER APPLICATIONS September 12–17, 2021 Tomsk, Russia ABSTRACTS GENERAL SPONSOR Special Systems. Photonics, St. Petersburg, Russia CONFERENCE ORGANIZERS Institute of Atmospheric Optics SB RAS Institute of High Current Electronics SB RAS Tomsk State University Tomsk Polytechnic University CONFERENCE SPONSORS Ministry of Education and Science of Russian Federation, Russia Russian Academy of Sciences, Russia Siberian Branch of Russian Academy of Science, Russia Laser Association, Russia  CONFERENCE SPONSORS TOPAZ Research and Inculcation Enterprise, Tomsk, Russia Young Scientists Counsil IAO SB RAS, Tomsk, Russia SP Equipment, Novosibirsk, Russia Azimut Photonics, Moscow, Russia LOTIS TII, Minsk, Belarus Special Systems. Photonics, St.-Petersburg, Russia CLZ Ltd, Moscow, Russia Leningrad Laser Systems, St.-Petersburg, Russia MEDIA SPONSORS Atmospheric and Oceanic Optics Journal, Tomsk, Russia Photonics Journal, Moscow, Russia  Tomsk, 2021  16  YOUNG SCIENTISTS SESSION SESSION Y  current in combination with an ICCD camera, the study of the generation of REs with reference to the dynamics of streamer formation was performed. The reported study was performed within the framework of the State assignment of the IHCE SB RAS, Project No. 0291-2021-0014 (FWRM-2021-0014) as well as was funded by RFBR, Project No. 20-02-00733. Y-13  PHOTOPHYSICAL INVESTIGATION AND THEORETICAL MODELING OF STRUCTURE ON THE EFFICIENCY OF SUBSTITUTED DIAZINES  AS EMITTERS FOR OLEDS E.V. Verbitskiy1,2, A.E. Kurtcevich3, L.G. Samsonova3, and R.M. Gadirov3 1Institute of Organic Synthesis UB RAS, 22 Kovalevskaya St., 620108, Ekaterinburg, Russia, charushin@ios.uran.ru; 2Ural Federal University, 19 Mira St., 620002, Ekaterinburg, Russia, contact@urfu.ru; 3Tomsk State University, 36 Lenina Ave., 634050, Tomsk, Russia, koall1996@yandex.ru A series of novel pyrazine quinoxaline derivatives D-A and D-π-A structures is synthesized. The photo- and electroluminescent properties of the obtained compounds were studied [1]. In this report, we provide a theoretical explanation of the mechanisms of the processes of delayed luminescence occurring in the presented structures. All calculations were carried out in the quantum chemical software package Orca 4.2.1 [2, 3] using stationary and time dependent density functional theory (DFT and TD-DFT). The geometry of the ground and first excited states was simulated; a diagram of the energy levels of molecules for triplet and singlet states was constructed. All compounds are characterized by a close to orthogonal arrangement of the donor and acceptor fragments of the molecule in the excited state. This leads to a low spatial overlap of the HOMO and LUMO, which favorably affects the quantum yield of delayed fluorescence. Analysis of Jablonski diagrams in comparison with experimental data has shown [1] that the test compound delayed fluorescence occurs by several mechanisms, including both the thermally activated delayed fluorescence (TADF) through the high triplet state (so-called “hot-excitons” mechanism – HE) and triplet triplet annihilation (TTA). In the first case the energy gap between S1 and T2 states was close to zero, when for the TTA cases the S1 state was approximately halfway between T1 and T2 states. The fact that delayed fluorescence occurs via the HE mechanism is explained by the different nature of the T1 and T2 states. This leads to little interaction between them. So, the process of nonradiative relaxation in the T1 state is extremely slowed down.  1. Verbitskiy E.V. et al. The effect of molecular structure on the efficiency of 1, 4-diazine–based D–(π)–A push-pull systems for non-doped OLED applications // Dyes and Pigments. 2021. V. 187. 109124. 2. Neese F.  The ORCA program system, Wiley Interdiscip. Rev.: Comput. Mol. Sci., 2012. 2. P. 73–78. 3. Neese F. Software update: the ORCA program system, version 4.0, Wiley Interdiscip. Rev.: Comput. Mol. Sci., 2017. 8, e1327. 

Photophysical investigation and theoretical modeling of structure on the efficiency of substituted diazines as emitters for OLEDs

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Photophysical investigation and theoretical modeling of structure on the efficiency of substituted diazines as emitters for OLEDs

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