| Abstract [eng] |
In this work acridan-, carbazole- and imidazole-based organic compounds for optoelectronic devices where synthesized and investigated. Computer calculations were used to calculate the most probable ground and excited states geometric structures of three-donor-fragment compounds. Thermal, electrochemical and photophysical properties of compounds were investigated. Theoretical and experimental calculation results where compared. All three-donor-fragment compounds absorb radiation up to 400 nm, and are characterized by delayed fluorescence emission. Carbazole – acridan compound solution emission band peak is around 420 nm, while compound made of only carbazole moieties solution emission band peak is around 392 nm. The investigation of compounds solutions emission showed, that difference between singlet and triplet energy states is smaller in carbazole – acridan compound, however, emission measurements from degassed solutions showed triplet excitons involvement in fluorescence. Bipolar carbazole – imidazole solutions absorb radiation up to 350 nm. The fluorescence band peaks of compounds solutions are in the range of 398 – 399 nm. Investigation of carbazole – imidazole-based compounds solutions demonstrated, that compounds with two imidazole rings absorption and emission peaks are wider, compared with those containing one imidazole ring. Blue organic light emitting devices were made in inert environment. Devices were characterized by 4 – 4.8 V turn-on voltage. The best device demonstrated 1.1 % external quantum efficiency and 1030 cd/m2 brightness. The technological scheme of carbazole – imidazole-based compounds with tert-butyl groups synthesis is reported. |
