Synthesis and luminescent properties of pentacene derivatives having a chromophore

We introduced carbazole and fluorene moieties into pentacene compound for comparing optical and EL properties together. The structure was identified by NMR, IR, UV–Visible spectroscopies and FAB-Mass analysis. 6,13-Bis(9,9-diethyl-9H-fluoren-2-ly)pentacene (DFP) and 6,13-bis(9-ethyl-9H-carbazol-3-yl)pentacene (ECP) showed similar red PL spectrum pattern and their maximum wavelengths appeared at 627 nm and 633 nm. ITO/m-MTDATA/NPB/Alq3:DFP (5%)/LiF/Al device showed red EL spectrum at 636 nm with 0.03 cd/A efficiency. ITO/m-MTDATA/NPB/Alq3:ECP (5%)/LiF/Al device also showed similar red EL spectrum at same range and higher efficiency (> 0.21 cd/A) than DFPs. We suppose the dopant EL property of pentacene compound can be changed as the electronic property and steric effect of 6,13-substituted moiety in 6- and 13-positions.