The development of non-doped oled based on donor-acceptor tetrachloropyridine-carbazole material with the emission in "deep-blue" region

Abstract

The development of efficient organic light emitting diodes (OLED) based on the phenomenon of intramolecular thermally activated delayed fluorescence (TADF), in the design of which there are no blue phosphorescent emitters based on rare earth metals, still remains a challenge in the development of new lighting systems and OLED displays. The article proposes a technological approach to the formation of new type of OLED, where the emitter is an organic donor-acceptor molecular material 9- (2,3,5,6-tetrachloropyridin-4-yl) -9H-carbazole (4-CzPyCl4), in which electronic interaction between the donor and acceptor fragment plays a key role in the mechanism of delayed fluorescence. The design of the developed light-emitting heterostructure uses layer-by-layer formation of functional nanosized organic films, in contrast to traditional OLED designs of dark blue color radiation, which uses a guest-host systemThe external quantum efficiency of the developed OLED is 2.8%. The maximum brightness of 3,000 cd/m2 is reached at a voltage of 15 V. The chromaticity coordinates CIE (x, y) 1931 are (0.15, 0.13), which corresponds to the “dark blue” emitting spectral zone.