9,9-Diethyl-N,N-diphenyl-9H-fluoren-2-amine derivatives end-capped with various aromatics as blue emitters for OLEDs

ABSTRACT

To develop efficient blue emitters, we synthesized a series of 9,9-diethyl-N,N-diphenyl-9H-fluoren-2-amine derivatives end-capped with various aromatics using Suzuki coupling reaction and Buchwald-Hartwig amination. To investigate their electroluminescent properties, multilayer devices were fabricated in following structures: Indium-tin-oxide (ITO) (180 nm)/ N,N′-diphenyl-N,N′-(1-napthyl)-(1,1′-phenyl)-4,4′-diamine (NPB) (50 nm)/ blue emitters (30 nm)/ bathophenanthroline (Bphen) (30 nm)/ 8-hydroxyquinolatolithium (Liq) (2 nm)/ Al (100 nm). All devices showed the blue emissions. Particularly, a device using 9,9-diethyl-7-(10-(10-(naphthalen-2-yl)anthracen-9-yl)anthracen-9-yl)-N,N-diphenyl-9H-fluoren-2-amine showed the efficient blue emission with 5.12 cd/A, 2.33 lm/W, and 3.94% of a luminous, power, and external quantum efficiency at 20 mA/cm², respectively and CIE (x, y) coordinates of (0.15, 0.15) at 6.0 V.

KEYWORDS:

• Blue OLEDs
• fluorene
• anthracene
• Suzuki coupling reaction
• fluorescence

Funding

This research was supported by the Basic Science Research Program through the NRF funded by the Ministry of Education, Science and Technology, South Korea (NRF 2013R1A1A2A10008105) and (NRF- 2015R1A6A1A03031833).