研究目的

Development of efficient electroactive organic compounds is prerequisite for the fabrication of highly efficient OLEDs and other optoelectronic devices. A combination of donor and acceptor moieties in a single molecule enables to obtain efficient light-emitting materials exhibiting useful phenomena which allow to harvest triplet excitons formed under electrical excitation and convert them into light such as intramolecular and intermolecular (exciplex-based) thermally activated delayed fluorescence, room temperature phosphorescence (RTP), triplet-triplet annihilation etc.

研究成果

Synthesis and properties of donor-acceptor derivatives of 2- or 4-(trifluoromethyl)benzene and 2,7-di-tert-butyl-9,9-dimethylacridine as luminophores with multicolour emission of different nature (falling in range from deep blue to yellow) were studied. Efficient exciplex systems were identified owing high triplet-energy values of the compounds which exceeded 3.1 eV. Using the synthesized compounds as light-emitting materials, highly efficient exciplex-based OLEDs were developed exploiting good hole injection properties of the compounds in solid-state (ionization potentials of 5.63/5.69 eV). In the best case, high maximum current, power and external quantum efficiences of 29.5 cd/A, 29.1 lm/W and 8.2 % respectively were achieved for the devices based on exciplex electroluminescence.

研究不足

The study demonstrates the potential of acridan-based luminophores for OLED applications, but the efficiency of exciplex systems is still a challenge due to large red shifts of emission spectra and long radiative lifetimes, which tend to diminish photoluminescence quantum yield (PLQY) as well as electroluminescence (EL) performance.