Fused Methoxynaphthyl Phenanthrimidazole Semiconductors as Functional Layer in High Efficient OLEDs

Efficient hole transport materials based on novel fused methoxynaphthyl phenanthrimidazole core structure were synthesised and characterized. Their device performances in phosphorescent organic light emitting diodes were investigated. The high thermal stability in combination with the reversible oxidation process made promising candidates as hole-transporting materials for organic light-emitting devices. Highly efficient Alq 3 -based organic light emitting devices have been developed using phenanthrimidazoles as functional layers between NPB [4,4-bis( N -(1-naphthyl)- N -phenylamino)biphenyl] and Alq 3 [tris(8-hydroxyquinoline)aluminium] layers. Using the device of ITO/NPB/ 4 /Alq 3 /LiF/Al, a maximum luminous efficiency of 5.99 cd A −1 was obtained with a maximum brightness of 40,623 cd m −2 and a power efficiency of 5.25 lm W −1 .