Fluorine effects in new indenofluorenedione derivatives for electron transporting layer in OLED devices.

New three indenofluorenedione derivatives were synthesized and proposed for electron transporting layer (ETL). Three compounds are indeno[1,2-b]fluorene-6,12-dione (IF-dione), 2,8-Difluoro-indeno[1,2-b]fluorene-6,12-dione (Mono-F-lF-dione), and 1,2,3,7,8,9-Hexafluoro-indeno[1,2- b]fluorene-6,12-dione (Tri-F-IF-dione). UV-visible (UV-Vis) absorption of three compounds in THF solution state showed different absorption maximum values as follows: 292, 318 and 334 nm (IF-dione), 289, 314 and 329 nm (Mono-F-IF-dione), 285, 319 and 334 nm (Tri-F-IF-dione). Three compounds were inserted between emitting layer (EML) and cathode electrode as an ETL in OLED device: ITO/2-TNATA (60 nm)/NPB (15 nm)/Alq3 (30 nm)/synthesized compounds (30 nm)/LiF (1 nm)/Al (200 nm). I-V characteristics of three devices were investigated at 20 mA/cm2. Operating voltages of three compounds were 7.06 V (IF-dione), 6.42 V (MonoF-IF-dione), 5.36 V (TriF-IF-dione), respectively.