Novel low-bandgap donor–acceptor thiophene-phenylene co-oligomers for light-emitting semiconductor devicesстатьяИсследовательская статья
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Дата последнего поиска статьи во внешних источниках: 26 июня 2024 г.
Аннотация:Thiophene-phenylene co-oligomers (TPCOs) have shown their high potential for organic light-emitting devices because of their high luminescence and efficient charge transport. However, unsubstituted TPCOs have relatively wide optical bandgaps and the high-lying lowest unoccupied molecular orbital (LUMO) energies so that efficient electron transport is a challenge. Electron-withdrawing groups (EWGs) and fluorinated fragments embedded into the TPCO molecule structure could result in the lower LUMO energy and narrower optical bandgap. Here, we report the synthesis of two novel TPCOs series with either phenylene or perfluorinated phenylene central core and end-capped with various EWGs (aldehyde, 2-ethylhexyl cyanoacetate, hexyl rhodanine and dicyanorhodanine) and with long alkyl terminal and side chains increasing the solubility. All the oligomers synthesized were found to be thermally stable and crystalline materials with relatively low LUMO energies (down to −3.50 eV), narrow bandgaps (down to 1.9 eV), and efficient photoluminescence in the green – deep red spectral regions both in solution and solid-state. The TPCOs with 2-ethylhexyl cyanoacetate EWG were crystallized in large-area single-crystal monolayers, which showed strongly polarized photoluminescence and demonstrated their high potential as active layers in solution-processed single-layer organic light-emitting transistors.This work was supported by the Russian Science Foundation (grant #19-73-10198) and performed in the Enikolopov Institute of Synthetic Polymer Materials of Russian Academy of Sciences (ISPM). The works on 2D films, monolayers and OLETs were supported by the Russian Science Foundation (grant #18-12-00499) and performed in ISPM. NMR spectra of oligomers were recorded using the equipment of Collaborative Access Center “Center for Polymer Research” of ISPM under financial support from Ministry of Science and Higher Education of the Russian Federation (topic FFSM-2021-0005). The device fabrication/characterization and the studies of 2D films were done by using the equipment purchasedunder the Lomonosov Moscow State University Program of Development. R.S.F. thanks the Theoretical Physics and Mathematics Advancement Foundation BASIS for support of his Ph.D. studies.