Synthesis and characterization of organic materials for organic light-emitting diodes (OLEDs)

We report on the synthesis and characterization of triphenylamine substituted fluorine as the both of the new blue light-emitting and hole-transporting materials for organic light-emitting diodes (OLEDs). The target molecules were synthesized using Suzuki cross-coupling reaction of boronic acid and aryl halides. The desired molecules were soluble in all common organic solvents at room temperature. The chemical structures of target molecules, 2,7-bis(4-(diphenyl-4-yl))-9,9-bis(4-diphenylaminophenyl)fluorine (BPTF), 2,7-bis(2-( diphenyl-4-yl)vinyl)-9,9-bis(4- diphenylaminophenyl)fluorine) (VBPTF), 2,7-bis(4-(carbazol-9-yl)-4- diphenyl)-9,9-bis(4- diphenyl aminophenyl)florene (CBPTF), 2,7-bis(4-(carbazol-9-yl)-2-methyldiphenyl-4-yl)-9,9-bis(4- diphenyl aminopheny) fluorine (CMBPTF), 2,7-bis(4- diphenylaminophenyl)-9,9-bis(4- diphenylaminophenyl)fluorine (2TTF), 2-pyrenyl-1-yl-7-(4- diphenylaminopheyl)-9,9-bis(4- diphenylaminophenyl)fluorine (TPTF), 2,7-bis(pyrenyl-1-yl)-9,9-bis(4- diphenylaminophenyl)fluorine (2PTF), 2,7-bis(pyrenyl-1-yl)-9,9-(4,4’,4’’,4’’’-tetrakispyrenyl-bis(4- diphenylaminophenyl))fluorine (2T6PTF),4,4’,4’’,4’’’-tetrakispyrenyl(2,7-bis(4- diphenylaminophenyl)))-9,9-bis-n-hexly florene (2T4PF), 4,4’-bis(carbazol-9-yl)biphenyl (CBP), 4,4’-bis (3,6-di(tert-butylcarbazol)-9-yl)) biphenyl (TCBP),4,4’-bis(3,6-di(tert-butylcarbazol)-9-yl)-2,2’-dimethylbiphenyl (TCDBP), 4,4’-bis(carbazol-9-yl)-2,2’-dimethylbiphenyl (CDBP), 4,4’,4’’,4’’’-tetrakis(3,6-di(tert-butyl carbazol-9-yl)carbazol-9-yl)-2,2’-dimethylbiphenyl (4TCDBP), 4-(4-(5-(1,3-dioxoindan-2-yl idenemethyl)-2-thienyl)carbazol-9-yl)biphenyl (ITBC), 4-(4-(5-(1,3-dioxoindan-2-ylidene methyl1)-2-thienyl) carbazol-9-yl)-2,2-dimethylbiphenyl (ITMBC) and (4-(5-(1,3-dioxoindan-2-yl idenemetyl1)-2-thienyl)carbazol-9-yl)-9,9-dihexylfluorene (ITFC) were confirmed by 1H-NMR and 13C-NMR, and FTIR techniques. UV-vis absorption spectra of target molecules showed a wide absorption bands containing characteristic absorption band of both the triphenylamine (300 nm) and the fluorine core ranging from 360-378 nm. All compounds exhibited a blue fluorescence with emission max ranging from 435-484 nm. They showed amorphous properties with high transition temperatures in the range of 90-277 C. The emission spectra of all compounds are in blue region and high quantum yield efficiency (F) in the range of 0.30-0.88. The devices structure used in this study is ITO/PEDOT:PSS/emitter/BCP[7nm] /LiF/Al where all target molecules were as emitter. The 2PTF-based devices displayed a low turn on voltage of 4.4 V and a maximum luminance of 5,850 cd/m2 at voltage of 9.4 V. The configuration of 2PTF, using as hole-transporting is ITO/PEDOT:PSS/HTL/Alq3/LiF/Al. The 2PTF-based devices displayed a low turn on voltage of 4.4 V and a maximum luminance of 19,130 cd/m2 at voltage of 9.6 V. They have potential applications as the both of light-emitting and hole-transporting materials for organic light-emitting diodes (OLEDs).