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.

Automated summary

Fluorene-based molecules are widely used in organic light emitting diodes (OLEDs). Two new materials, FLU-DTPA and FLU-DCAR, were designed and synthesized for OLED applications. The FLU-DCAR based yellow phosphorescent device showed high current and external quantum efficiencies, outperforming the triphenylamine-based FLU-DTPA. Additionally, non-doped fluorescent devices fabricated with the newly synthesized molecules exhibited deep blue emission.