New high efficiency green light emitting phosphorescent devices with emission layers of [TCTA/TCTA:TAZ/TAZ]:Ir(ppy)₃ have been fabricated and evaluated in this paper. Among the devices having different thicknesses of TCTA:TAZ mixed layer in the total 300-thick host of TCTA(80Å)/TCTA:TAZ (50~100Å)/TAZ, the device with host of TCTA(80Å)/TCTA:TAZ(90Å)/TAZ(130Å) showed the best electroluminescent characteristics with the current density of 95 mA/㎠ and luminance of 25,000 cd/㎡ at an applied voltage of 10V. The maximum current efficiency was 52 cd/A under the luminance of 400 cd/㎡.