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

摘要

Au/Vanadium pentoxide $(hbox{V}_{2}hbox{O}_{5})$ films on indium tin oxide (ITO) as composite anodes for hole injection in organic light-emitting devices (OLEDs) have been investigated. The device with $hbox{ITO/Au}(hbox{6} hbox{nm})/hbox{V}_{2} hbox{O}_{5}(hbox{6} hbox{nm})$ 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 $hbox{V}_{2}hbox{O}_{5}$ 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 $hbox{ITO/Au}/hbox{V}_{2}hbox{O}_{5}$ OLED is $sim$3.5 cd/A, which is higher than that of the ITO/Au anode device ($sim$1.1 cd/A) and $ hbox{ITO}/hbox{V}_{2}hbox{O}_{5}$ OLED of $sim$ 2.8 cd/A.