•Two novel solution-processable blue fluorescent compounds were synthesized and characterized.•Both of them showed obvious HLCT characteristics.•The maximal efficiencies of p-DTPABI-Cz were up to 3.71 cd/A, 2.33 lm/W, and 2.88%.Two novel dual emitting core hybridized local and charge-transfer emitters of 4′,4‴-(1,1′-((9-(heptadecan-9-yl)-9H-carbazole-2,7-diyl)bis(4,1-phenylene))bis(1H-p-henanthro[9,10-d]imidazole-2,1-diyl))bis(N,N-diphenyl-[1,1′-biphenyl]-4-amine) and 4′,4‴-(1,1′-((9-(heptadecan-9-yl)-9H-carbazole-2,7-diyl)bis(3,1-phenylene))bis(1H-phenanthro[9,10-d]imidazole-2,1-diyl))bis(N,N-diphenyl-[1,1′-biphenyl]-4-amine) were designed and synthesized by introducing two hybridized local and charge-transfer units for single-layer, solution-processable, and blue organic light-emitting diodes (OLEDs). Their absorption, photoluminescence, hybridized local and charge-transfer characteristics, thermal stability and electrochemistry were systematically studied. The single-layered devices by using them as emitters showed efficient blue emission with a maximum brightness 5521 cd/m2 for 4′,4‴-(1,1′-((9-(heptadecan-9-yl)-9H-carbazole-2,7-diyl)bis(4,1-phenylene))bis(1H-p-henanthro[9,10-d]imidazole-2,1-diyl))bis(N,N-diphenyl-[1,1′-biphenyl]-4-amine) and 4403 cd/m2 for 4′,4‴-(1,1′-((9-(heptadecan-9-yl)-9H-carbazole-2,7-diyl)bis(3,1-phenylene))bis(1H-phenanthro[9,10-d]imidazole-2,1-diyl))bis(N,N-diphenyl-[1,1′-biphenyl]-4-amine). The maximal efficiencies of the former were up to 3.71 cd/A, 2.33 lm/W, and 2.88%. Furthermore, at the high luminescence, the device still indicated good performance with relative low efficiency roll-off. The relationships of structures and properties were also discussed. Most importantly, we provided a new method to construct solution processable small molecules for highly efficient single-layer OLEDs.

•Novel blue fluorescent emitters based on spirofluorene derivatives were synthesized and characterized.•The nondoped electroluminescent devices based on them show high efficiency and blue emissions.•The results are demonstrated to be tunable electroluminescence from sky-blue to deep-blue emission.Two novel benzimidazole-attached spiro[benzofluorene] derivatives, 2,2′-(spiro[benzo[c]fluorine-7,9′-fluorene]-5,9-diylbis(4,1-phenylene))bis(1-phenyl-1H-benzo[d]imidazole) and 2,2′-(spiro[benzo-[de]anthracene-7,9′-fluorene]-2′,3-diylbis(4,1-phenylene))bis(1-phenyl-1H-benzo[d]imidazole), were prepared by a Suzuki coupling reaction. Their photophysical and photochemical properties were studied systemically. The fluorescent organic light-emitting diodes were fabricated by using them as the emitters, all of them showed strong blue emission. Interestingly, from the benzoanthracene derived compound a high color purity was found with Commission de L'Eclairage 1931 chromaticity coordinates of (0.15, 0.10) and an efficiency of 1.96 cd/A. To the best of our knowledge, this is the first time to obtain a deep-blue emission with spiro[benzofluorene] derivative in a nondoped device.

•Novel host materials based on arylamine and phenanthroimidazole moieties.•High triplet energy hosts for phosphorescent OLEDs.•Highly efficient green phosphorescent OLEDs.Two novel host materials, 2-(4,4″-di(9H-carbazol-9-yl)-[1,1′:3′,1″-terphenyl]-5′-yl)-1-(4-(trifluoro-methyl)phenyl)-1H-phenanhro[9,10-d]imidazole (DCzBPI) and N4,N4,N4″,N4″-tetraphenyl-5′-(1-(4-(trifluoromethyl)phenyl))-1H-phenanthro-[9,10-d] (DTPABPI), were designed and synthesized. The electroluminescence (EL) characteristics by using them as host materials were investigated. Results were found both of them showed good performance, especially for DCzBPI. The maximal external quantum efficiency is up to 21.2% and the brightness is up to 63,610 cd/m2 with current efficiency of 53.8 cd A−1.