Highly efficient blue phosphorescent OLEDs based on 1, 3, 5-tri (9H-carbazol-9-yl)benzene host material

Hightly efficient blue phosphorescent organic light emitting diodes(OLEDs) based on a host material 1,3,5-tri(9H-carbazol-9-yl)benzene(TCzP) doped(iridium(Ⅲ)[bis(4,6-difluorophenyl)-pyridinato-N,C2′]picolinate)(FIrpic) were fabricated,and a double-emitting layer device was also manufactured.The maximum brightness of 11 957 cd/m2,peak current efficiency of 18.8 cd/A with Commission Internationale de L'Eclairage(CIE) coordinates of(0.17,0.37) were obtained.The emission peak wavelength of 472 nm with its shoulder peaking at 496 nm were observed.Even at high brightness of 1 000 cd/m2,the current efficiency remains 13.5 cd/A.The experimental results indicate that high triplet energy and hole mobility for a host material are very important to achieve highly efficient blue phosphorescent device.