| abstract |
An organic light-emitting device comprising: an anode; a cathode; a first light-emitting layer between the anode and the cathode, the first light- emitting layer comprising a fluorescent light-emitting material having a triplet excited state energy level T 1F and a triplet- triplet annihilation (TTA) promoter having a triplet excited state energy level T IT wherein T 1F > 1T ; and a second light-emitting layer between the anode and the cathode and adjacent to the first light-emitting layer, the second light-emitting layer comprising a phosphorescent material having a triplet excited state energy level T 1P wherein T 1P > T 1T . |