Organic electroluminescent devices with molecularly doped polymers and anode interface phthalocyanine layer

We studied the properties of organic electroluminescent devices using molecularly doped polymers as a hole transport layer and having a metal-free phthalocyanine (H₂Pc) layer between anode and hole transport layer. A vacuum-deposited H₂Pc metastable layer was converted to a more stable microcrystalline layer by dichloromethane solvent treatment. The devices exhibited good current–voltage and luminance properties. Because the activation energy of carrier transport for the devices with H₂Pc was almost the same as that for the devices without it, it is considered that the H₂Pc layer in this device is electrically inert. This means that improved contact efficiency may be obtained at the anode interface due to the introduction of the H₂Pc layer. © 1997 John Wiley & Sons, Ltd.