Blue Non-Doped Organic Light Emitting Diodes Based on a Novel Donor–Acceptor Molecule

Blue organic electroluminescent devices with the structure of ITO/NPB (40 nm)/TcTA (5 nm)/TPAMI (x nm)/TPBi (20 nm)/LiF (0.5 nm)/Al (100 nm), (x = 10, 15, 20, 25) were successfully fabricated in this study. The N,N'-diphenyl-4'-(1-phenyl-1H-benzl[d]imidazol-2-yl)-[1,1'-biphenyl]-3-amine (TPAMI) blue fluorescent dye was used as single light emitting layer. The effects of TPAMI layer on luminescence performance by the devices were investigated in detail. All the four devices were entirely in the blue region and there was a slight change of Commission International de l'Eclairage coordinates at (0.17, 0.17). When the TPAMI thickness was fixed at 15 nm, the maximum luminance was 3080 cd/m² and the current efficiency was 1.31 cd/A.