ИСТИНА

Liquid organic luminophores are a relatively new and class of materials, which have high processability owing to their fluidic nature and efficient fluorescence in pristine state [1]. However, the structure-property relationships of such compounds remain poorly understood. In addition, they exhibit luminescence in a limited short-wavelength region of the spectrum. The introduction of electron-withdrawing units and solubilizing groups of various nature into these molecules allows fine tuning of the properties of the obtained materials. The absence of aggregation and the need to use solvents increases the manufacturability and environmental friendliness of the processes of manufacturing devices based on such functional materials and opens up new areas of their application. In the course of this work, new oligomers based on 2,2'-biphenyl-4,4'-diylthiophene with linear and branched alkyl, trialkylsilyl with different lengths and branching of alkyls and alkyloligodimethylsiloxane solubilizing groups were synthesized to study the influence of the type, length and branching degree of solubilizing groups on thermal stability, aggregate state, phase behaviour, rheology and optical properties [2]. When the most effective solubilizing group for liquefaction was identifying, the series of novel liquid benzothiadiazole-based luminophores containing phenylene or thiophene units with terminal trihexylsilyl groups on each side of the central core were synthesized. The high purity and specified structure of all the compounds obtained was proved by a complex of modern research methods. The influence of the nature, length and branching of the solubilizing groups and type of π-conjugated core on the optical properties, rheology, phase behavior and thermal stability of luminophores has been studied. Based on this study, the most suitable group was selected to reduce aggregation in a condensed state, using which new liquid luminophores of oligomeric structure were obtained, emitting light in various ranges of the visible spectrum. This work was supported by the Russian Foundation for Basic Research (grant № 18-33-20224). NMR and UV–vis spectra were recorded using the equipment of Collaborative Access Center ‘Center for Polymer Research’ of Enikolopov Institute of Synthetic Polymeric Materials of the Russian Academy of Sciences with the financial support from the Ministry of Science and Higher Education of the Russian Federation (Contract 0071-2021-0005).