Efficient green-electroluminescent devices using [1,3,4]-oxadiazole derivatives as hole- blocking and electron transporting materials

Abstract

The new amorphous molecular material, 2,5-bis-(4-triphenylsilanyl-phenyl)- [1,3,4]oxadiazole, that functions as good hole blocker as well as electron transporting layer in the phosphorescent devices. The obtained material forms homogeneous and stable amorphous film. The new synthesized showed the reversible cathodic reduction for hole blocking material and the low reduction potential for electron transporting material in organic EL devices. The fabricated devices exhibited high performance with high current efficiency and power efficiency of 45 cdJA and 17.7 lm/W in 10 mA/cm2, which is superior to the result of the device using BAIq (current efficiency: 31.5 cdJA and power efficiency: 13.5 lm/W in 10 mA/cm2) as well known hole blocker. The ITO/DNTPD/a-NPD/6% Ir(ppy)3 doped CBP/2,5- bis.(4-triphenylsilanyl-phenyl)-[ 1 ,3,4joxadiazole as both hole blocking and electron transporting layer/Al device showed efficiency of 45 cdJA and maximum brightness of 3000 cdim2 in 10 mA/cm2. Copyright © 2007 Materials Research Society.