Characteristics of vanadium-doped indium oxide thin films for organic light-emitting diodes fabricated by spray chemical vapor deposition

An indium oxide transparent electrode for organic light-emitting diodes was fabricated by the inexpensive spray chemical vapor deposition method. The high work function (5.1 eV) necessary for a transparent anode and a hole-injection layer was successfully achieved with a vanadium doping concentration of 1.5 at. % V without any significant increase in resistivity and surface roughness or loss of transparency. The effect of vanadium doping on indium oxide was systematically investigated. The resistivity, average transmittance in the visible range, and surface roughness (Ra) were 1.08 × 10−3 Ωcm, 84%, and 4.0 nm, respectively, for the vanadium-doped indium oxide.