Patent ID: 7816173

Claim:
A method for improving device efficiency of an organic light-emitting device comprising: a cathode; an anode; and a layer structure disposed between the cathode and the anode; the layer structure comprising: a hole source region made of a first source material disposed adjacent to the anode; an electron source region made of a second source material disposed adjacent to the cathode; and an emissive region disposed between the hole source region and the electron source region, such that the emissive region is immediately adjacent to the hole source region and immediately adjacent to the electron source region, the emissive region made of at least one organic host material doped with one or more luminescent dopants, each of the emissive region, the hole source region and the electron source region having an electrical conductivity, wherein at least one of the first source material and the second source material comprises an inorganic material, said method comprising the steps of: introducing ions into the first source material so as to achieve the electrical conductivity of the hole source region between 10 −8 to 10 2 S/cm; and introducing ions into the second source material so as to achieve the electrical conductivity of the electron source region between 10 −8 to 10 2 S/cm; such that the electrical conductivity of the emissive region is lower than the electrical conductivity of the immediately adjacent hole source region and the immediately adjacent electron source region; and that the electrical conductivity of the cathode and the anode is higher than 10 2 S/cm, and wherein the hole source region comprises one or more layers containing TCNQ, and said one or more TCNQ containing layers comprise a layer of F 4 -TCNQ:WO 3 .