The study of an inducer-layer between red and blue emission for white organic light-emitting diodes

The white organic light-emitting diodes (WOLED) using, phosphorescent dopant, iridium (III) bis[(4,6-di-fluorophenyl)-pyridinato-N, C2] picolinate (Firpic) and fluorescent dopant, 4-(dicyanomethylene)-2-t-butyl-6(1,1,7,7- tetramethyliul-olidyl-9-enyl)-4H-pyran (DCJTB) were fabricated by employing two different types of inducer-layer such as N, N´-dicarbazoly-3,5-benzene (mCP) and 4,7-diphenyl-1,10-phenanthroline (Bphen). Luminous efficiency, max luminance, and Commission Internationale de l´Eclairage (CIE_x,y) coordinates of the WOLED using Bphen as inducer layer were 8.72 cd/A at 5.61mA/cm², CIE_x,y(x=0.27, Y=0.37) at 11.11mA/cm², and 12330cd/m² at 205.82mA/cm², respectively. These results demonstrated that Bphen attributed hole-electron recombination zone controlling electron injection through 3.2eV lowest unoccupied molecular orbital (LUMO) energy level and hole blocking by 6.4eV highest occupied molecular orbital (HOMO) energy level.