White phosphorescent organic light emitting devices

Abstract

A device is provided. The device includes an anode, a cathode and a double emissive layer disposed between the anode and the cathode. The double emissive layer includes a first organic emissive layer and a second organic emissive layer. The first organic emissive layer includes a first phosphorescent material having a concentration of 15-35 wt % in the first organic emissive layer, and a peak emissive wavelength in the visible spectrum at a wavelength between 400 nm and 500 nm; and a first host material having a triplet energy at least 0.2 eV and not more than 1.0 eV greater than the triplet energy of the first phosphorescent material. The second organic emissive layer includes a second phosphorescent material having a concentration of 15-35 wt % in the second organic emissive layer, and a peak emissive wavelength in the visible spectrum at a wavelength between 500 nm and 600 nm, and a third phosphorescent material having a concentration of 0.1-3 wt % in the second organic emissive layer, and a peak emissive wavelength in the visible spectrum at a wavelength between 600 nm and 700 nm. The second host material has a triplet energy greater than that of the third phosphorescent emissive material. The second organic emissive layer is disposed between the anode and the cathode, and is adjacent to the first organic emissive layer. The device also includes a blocking layer disposed adjacent to the second organic emissive layer and between the second organic emissive layer and the anode. The blocking layer has a lowest unoccupied molecular orbital that is at least 0.1 eV greater than the lowest unoccupied molecular orbital of the second host material. The device also includes a hole transport layer disposed between the blocking layer and the anode. At least one of the anode and the cathode is transmissive.

Dependencies are inferred from the claim text.