ИСТИНА

The active development of organic electronics and photonics leads to the search for new highly efficient functional organic materials possessing semiconducting, light emitting or light harvesting properties. A large number of works are devoted to the synthesis and study of novel π conjugated molecules for use in organic field-effect transistors, light-emitting diodes, solar cells, plastic scintillators, spectral shifters and other devices. A wide variety of molecular structures of organic molecules leads to different conjugation pathways within the molecule, which influence their HOMO and LUMO levels, bandgap, and hence their optical and semiconducting properties. Liner-, cross- and omniconjugation introduced by J.C. Hummelen in 2004 not only lead to understanding the difference in optical properties of many conjugated molecules of various structure, but also allows to designing novel organic molecules with linear π-conjugated pathways between all the substituents [1]. In this presentation, several classes of organic molecules with different conjugation patterns, peculiarities in their synthesis, properties and application in organic electronic and photonic devices will be compared (Fig. 1). Branched molecules based on 1,3,5-substituted benzene initially considered by Hummelen as non-conjugated were later accepted as meta-conjugated molecules. Branched oligoarylsilanes were found to be non-conjugated as a whole molecule, leading to molecular antenna properties with ultrafast intramolecular energy transfer between their branches [2]. Donor-acceptor molecules based on triphenylamine were found to be fully conjugated with internal energy transfer leading to low bandgaps [3]. Changing molecular structure of such molecules allows tuning their optical properties for various optoelectronics devices, even for such exotic as full-colour artificial retinas [4]. This work was financially supported by the Russian Science Foundation (grant 19-73-30028). 1. M.H. van der Veen, M.T Rispens, H.T Jonkman, J. C. Hummelen, Molecules with linear π-conjugated pathways between all substituents: omniconjugation. Adv. Funct. Mater. 2004, 14 (3), 215-223 2. S.A. Ponomarenko, N.M. Surin, M.S. Skorotetcky, O.V. Borshchev, S.A. Pisarev, E.A. Svidchenko, Yu.V. Fedorov, F. Molins, T. Brixner, Ultrafast Intramolecular Energy Transfer in Nanostructured Organosilicon Luminophore Based on p-Terphenyl and POPOP, J. Mater. Chem. C, 2019, 7(46), 14612 3. Yu.N. Luponosov, A.N. Solodukhin, D.O. Balakirev, N.M. Surin, E.A. Svidchenko, S.A.Pisarev, Yu.V. Fedorov, S.A. Ponomarenko, Triphenylamine-based luminophores with different side and central aromatic blocks: Synthesis, thermal, photophysical and photochemical properties, Dyes and Pigments, 2020, 179, 108397 4. M. Skhunov, A.N. Solodukhin, P. Giannakou, L. Askew, Yu.N. Luponosov, D.O. Balakirev, N.K. Kalinichenko, I P. Marko, S.J. Sweeney and S.A. Ponomarenko, Pixelated full-colour small molecule semiconductor devices towards artificial retinas, J. Mater. Chem. C, 2021, 9, 5858-5867