Synthesis and electro-optical properties of biphenyl analogues

Abstract

Three emitting materials containing a biphenyl core connected at both ends with phenoxazine or anthracene groups, 10-(3-(10 H-phenoxazin-10-yl)-6-phenylphenanthridin-8-yl)-10 H-phenoxazine ( DPoPP), 8-(anthracen-10-yl)-3-(anthracen-9-yl)-6-phenylphenanthridine ( DAnPP), and 2-(anthracen-10-yl)-7-(anthracen-9-yl)-4,5,9,10-tetrahydropyrene ( DAnTP) were synthesized via the C–N Ullmann coupling or C–C Suzuki-coupling reaction. Optical properties, thermal stabilities and molecular orbital energies were analyzed as a function of their molecular microstructure. The thermal stabilities of them were influenced by biphenyl core. On the other hand, their emissions were primarily affected by anthracene or phenoxazine end groups. Two compounds with anthracene moiety at both ends showed electronic band structures suitable for host materials for reported blue dopants. The double-layer OLED (organic light-emitting diode) devices, ITO/NPD/synthesized material/LiF/Al, containing the synthesized materials as emitting layer emitted yellowish-green ( DPoPP), greenish-blue ( DAnPP) and blue ( DAnTP).