Fluorene core with several modification by using donor type triphenylamine and carbazole derivatives for organic light emitting diodes

Fluorene based molecules have wide range of application in organic light emitting diodes (OLEDs). In our work, two new materials were designed and synthesized: N1-(4-(diphenylamino)phenyl)-N4,N4-diphenyl-N1-(9,9diphenyl-9H-fluoren-7-yl)benzene-1,4-diamine (FLU-DTPA) and N,N-bis(4-(9H-carbazol-9-yl)phenyl)-9,9diphenyl-9H-fluoren-2-amine (FLU-DCAR). These newly synthesized materials were applied as hole transporting material in yellow phosphorescent OLEDs. The FLU-DCAR based yellow phosphorescent device showed high current and external quantum efficiencies of 44.25 cd/A and 17.8%, respectively. The recorded efficiency of FLU-DCAR is better than that of triphenylamine based FLU-DTPA (32.54 cd/A, 12.8%) and reference 1,1-Bis [(di4-tolylamino) phenyl] cyclohexane TAPC (20.45 cd/A, 14.91%). Moreover, non-doped fluorescent devices fabricated to understand our newly synthesized molecules as dopant, and both molecules exhibited a deep blue emission.