Highly efficient ultra-deep blue organic light-emitting diodes with a wet- and dry-process feasible cyanofluorene acetylene based emitter

Abstract

This article describes the synthesis and characteristics of a cyanofluorene–acetylene conjugate based blue emitter C3FLA-2. In the host doped device, C3FLA-2 shows an EQE of 8.0% and CIExy of (0.156, 0.048).

Manipulation of Donor–Acceptor Interactions in Carbazole‐Based Emitters by Chromophore Choice To Achieve Near‐UV Emission

“…It is interesting to compare the absorption spectrum of 4b with the that of a previously reported compound containing a cyanofluorene unit instead of a cyanocarbazole unit . The slight increment in the absorption maximum of 4b is attributed to the electron richness of carbazole relative to fluorene.…”

“…Thus, the dye containing triphenylamine, 4d , exhibited a very low oxidation potential. It is interesting to compare the electrochemical behavior of 4b with that of the previously reported dye containing a cyanofluorene core instead of a cyanocarbazole core . The comparatively low oxidation potential of 4b is attributable to the electron richness of the carbazole core relative to that of the fluorene core.…”

“…Secondly, the dipolar relaxation is less pronounced, as the donor strength of carbazole is small compared with that of triphenylamine. The redshifted emission observed for 4b compared with that of its cyanofluorene analogue indicates the elongated π conjugation rendered by the carbazole scaffold over that for fluorene.…”

Blue organic light-emitting diodes based on phenyl-bridged fluoranthene and triphenylene derivatives

“…Recently, various blue emitters such as anthracene [12], fluorine [13], and carbazole [14,15], were developed to improve the EL efficiencies and life time for the practical applications. Among those are fluoranthene and triphenylene derivatives.…”

“…Hz, 2H) 13. C NMR (125 MHz, CDCl 3 ) [d ppm]: 140.7, 140.5, 140.2, 139.3, 138.0, 137.8, 136.6, 136.1, 135.9, 131.9, 131.1, 130.3, 129.6, 129.2, 129.0, 128.6, 128.5, 128.0, 127.8, 127.6, 127.5, 127.3, 126.6, 123.3, 122.8.…”