Low operating-voltage and high power-efficiency OLED employing MoO3-doped CuPc as hole injection layer

Effects of doping molybdenum oxide (MoO3) in copper phthalocyanine (CuPc) as hole injection layer in OLEDs are studied. A green OLED with structure of ITO/MoO3-doped CuPc/NPB/10-(2-benzothiazolyl)-2,3,6,7-tetrahydro-1,1,7,7-tetramethyl-1H,5H, 11H-(1)-benzopyropyrano(6,7,8-i,j) quinolizin-11-one (C545T): tris(8-hydroxyquinoline) aluminum (Alq3)/Alq3/LiF/Al shows the driving voltage of 4.4 V, and power efficiency of 4.3 lm/W at luminance of 100 cd/m2. The charge transfer complex between CuPc and MoO3 plays a decisive role in improving the performance of OLEDs. The AFM characterization shows that the doped film owns a better smooth surface, which is also in good agreement with the electrical performance of OLEDs.

► MoO3-doped CuPc layer as hole injection layer is effective for OLEDs. ► The charge transfer complex is important to improve the performance of OLEDs. ► The amount of charge transfer complex depends on MoO3 doping concentration.