US Patent 9153790 Organic electroluminescent device

An organic electroluminescence device including an anode, an emitting layer, a blocking layer, an electron-injecting layer and a cathode in sequential order; wherein the emitting layer contains a host and a dopant which gives fluorescent emission of which the main peak wavelength is 550 nm or less; the affinity Ad of the dopant is smaller than the affinity Ah of the host; the triplet energy ETd of the dopant is larger than the triplet energy ETh of the host; the triplet energy ETb of the blocking layer is larger than ETh; and the blocking layer includes an aromatic hydrocarbon compound.