ИСТИНА

Liquid organic luminophores prepared by covalently attaching bulky, flexible, and low-melting side chains at the periphery of π-conjugated 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 new areas of their application, such as emitting inks, OLEDs, electrets, scintillators and ect. In the course of this work, oligomers based on 2,2'-biphenyl-4,4'-diylthiophene with linear and branched alkyl, trialkylsilyl 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. Some of the obtained oligomers were tested as scintillation detectors. Due to the high concentration of active phosphor fragments per unit volume in such materials, which cannot be achieved by preparing a simple solution based on them, and the relatively high fluorescence quantum yield in the block (45 - 75%), effective scintillators based on these oligomers were created. This work was supported by the Russian Foundation for Basic Research (grant № 18-33-20224).