New spirobenzoanthracene derivatives with naphthylanthracene core: Synthesis and application in sky-blue fluorescent host materials

• New spiro[benzo[de]anthracene-7,9′-fluorene]-type two host materials were prepared.
• Two host materials are thermally stable with high Tg of <227 °C.
• Sky-blue fluorescence OLEDs with a color purity of (0.150, 0.217) were developed.
• Luminescence efficiency was 7.57 cd/A at 5.0 V with an external quantum efficiency of >5.15%.

Blue light-emitting host materials with a spiro[benzo[de]anthracene-7,9′-fluorene] core, 3-[10-(naphthalene-1-yl)anthracene-9-yl]spiro[benzo[de]anthracene-7,9′-fluorene] (NA-SBAF) and 3-[10-(naphthalene-1-yl)anthracene-9-yl]-1-methylspiro[benzo[de] anthracene-7,9′-fluorene] (NA-MSBAF), were designed and synthesized via coupling reactions. Introduction of a spiro group into the anthracene moieties lead to a reduction in crystallization tendency, and a high glass transition temperature was observed. Typical blue fluorescent organic light-emitting diodes with the configuration of ITO/N,N′-di(1-naphthyl)-N,N′-bis[(4-diphenylamino)phenyl]-biphenyl-4,4′-diamie (60 nm)/N,N,N′,N′-tetra(1-biphenyl)-biphenyl-4,4′-diamine (30 nm)/Host: Dopant (30 nm, 5%)/LG201 (ETL, 20 nm)/LiF/Al were developed using SBAF-type anthracene derivatives as a host material and p-bis(p-N,N-diphenyl-aminostyryl)benzene (DSA-Ph) as a sky-blue dopant material. A device obtained from NA-SBAF doped with DSA-Ph were compared with that of 9,10-dinaphthalene-2-yl-anthracene and showed blue color purity of 0.150 and 0.217, a luminance efficiency of 7.57 cd/A, and an external quantum efficiency >5.15% at 5.0 V.

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