Indenofluorene-Based Blue Fluorescent Compounds and Their Application in Highly Efficient Organic Light-Emitting Diodes

• Published in: European journal of organic chemistry Vol. 2012; no. 14; pp. 2748 - 2755
• Main Authors: Lee, Kum Hee, Kim, Seul Ong, Kang, Sunwoo, Lee, Jin Yong, Yook, Kyoung Soo, Lee, Jun Yeob, Yoon, Seung Soo
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.05.2012; WILEY‐VCH Verlag; Wiley; Wiley-VCH
• Subjects: Alicyclic compounds; Alicyclic compounds, terpenoids, prostaglandins, steroids; Chemistry; Chemistry, Organic; Condensed benzenic and aromatic compounds; Electrochemistry; Exact sciences and technology; Fused-ring systems; General and physical chemistry; Heterocyclic compounds; Heterocyclic compounds with only one n hetero atom and condensed derivatives; Luminescence; Organic chemistry; Organic light-emitting diodes; Photoelectrochemistry. Electrochemiluminescence; Photophysics; Physical Sciences; Preparations and properties; Science & Technology; Organic light-emitting diodes; Luminescence; DEVICES; Photophysics; DERIVATIVES; Fused-ring systems; BIPOLAR; Multilayer; Molecular structure; Nitrogen heterocycle; Carbazole derivatives; Horner Emmons reaction; Electroluminescence; Aluminium complex; Suzuki coupling; Organic light emitting diodes; Aromatic compound; Fluorescent compound; Chemical synthesis; Fluorene derivatives
• ISSN: 1434-193X; 1099-0690
• DOI: 10.1002/ejoc.201200117

Blue fluorescent compounds based on indenofluorene derivatives incorporating the (diphenylamino)arylvinyl group and di‐tert‐butylphenyl blocking units have been synthesized by Suzuki coupling and the Horner–Wadsworth–Emmons reaction. Their electroluminescence in multilayered OLEDs was examined; the devices have the structures ITO/DNTPD/NPB/MADN:blue dopant/Alq3/LiF/Al. A device with 7 % 2‐(3,5‐di‐tert‐butylphenyl)‐8‐(9,9‐diethyl‐2‐(diphenylamino)fluoren‐7‐ylethenyl)‐6,6,12,12‐tetraethylindeno[1,2‐b]fluorene (3) as blue dopant showed a luminous efficiency of 12.2 cd A–1, a power efficiency of 6.08 lm W–1, and an external quantum efficiency of 7.84 % at 20 mA cm–1 with CIE (Commission Internationale d'Énclairage) (x, y) coordinates of (0.148, 0.241) at 8.5 V. A deep‐blue OLED with CIE (x, y) coordinates of (0.153, 0.128) doped with 2‐(3,5‐di‐tert‐butylphenyl)‐8‐[9‐(3,5‐di‐tert‐butylphenyl)carbazol‐3‐ylethenyl]‐6,6,12,12‐tetraethylindeno[1,2‐b]fluorene (4) exhibited a luminous efficiency of 3.25 cd A–1, a power efficiency of 1.74 lm W–1, and an external quantum efficiency of 2.93 % at 20 mA cm–1. A series of indenofluorene derivatives incorporating the (diphenylamino)arylvinyl group and di‐tert‐butylphenyl blocking units have been synthesized and their photophysical and electroluminescent properties examined. In the case of device 3C, the use of 3 as dopant in the emitting layer led to blue emission with an external quantum efficiency of 7.8 % at 20 mA cm–1.