| abstract |
An OLED device comprises a cathode, an anode, and has therebetween a light emitting layer (LEL) comprising a phosphorescent emitting compound disposed in a host comprising a mixture of at least one electron transporting co-host and at least one hole transporting co-host, wherein there is present an electron transporting layer contiguous to the LEL on the cathode side and wherein there is present an EIL layer containing a heteroaromatic compound contiguous to the cathode. |