US Patent 9929358 Organic light-emitting devices

An organic light-emitting device including a first electrode; a second electrode opposite to the first electrode; an emission layer between the first electrode and the second electrode; and a hole transport region between the first electrode and the emission layer, wherein the emission layer includes at least one organometallic compound represented by Formula 1; and wherein the hole transport region includes at least one selected carbazole-based compound represented by Formula 2: