Indium Tin Oxide Modified by Au and Vanadium Pentoxide as an Efficient Anode for Organic Light-Emitting Devices

Au/Vanadium pentoxide (V
₂
O
₅
) films on indium tin oxide (ITO) as composite anodes for hole injection in organic light-emitting devices (OLEDs) have been investigated. The device with ITO/Au(6 nm)/V
₂
O
₅
(6 nm) anode shows improved current density-voltage characteristics as compared with the device with ITO/Au as anode. Hole injection is significantly reduced when Au was added on ITO as an anode. However, while a thin V
₂
O
₅
film is deposited on a Au anode, the barrier height is substantially reduced. The hole injection is facilitated, and the driving voltage of the device decreased by 10 V. In addition, the maximum current efficiency for the ITO/Au/V
₂
O
₅
OLED is ~3.5 cd/A, which is higher than that of the ITO/Au anode device (~1.1 cd/A) and ITO/V
₂
O
₅
OLED of ~2.8 cd/A.