DMIC-TRZ is commonly known as a universal host material for full-color TADF devices. DMIC-TRZ chemical structure consists of an electron accepting 2,4,6-triphenyl-1,3,5-triazine core and an electron donating indeno[2,1-b]carbazole pendant.
Example devices include the use of 5TCZBN, DMAC-BP and 4TCzTPN as sky blue, green, and orange TADF emitters. With DMIC-TRZ as the host, maximum external quantum efficiencies of 19.2%, 21.0% and 23.2% are achieved for the sky blue, green, and orange TADF devices, respectively. The finished TADF devices show ultra-low efficiency roll-off with above 90% of the maximum external quantum efficiencies being maintained even at a brightness of 2000 cd/m2. Three-color all-fluorescence WOLEDs with DMIC-TRZ as the host demonstrate remarkable external quantum efficiency of 31.0%, outstanding color rendering index of 93 with high color quality, and improved efficiency stability and long operational lifetime.
With strong electron-accepting ability, DMIC-TRZ can also form an exciplex with electron-donating materials such as TAPC. A TADF device based on the exciplex couple shows a maximum current efficiency of 25.12 cd/A when the ratio of DMIC-TRZ to TAPC is 6:1, with balanced charge carriers transport and efficient RISC process. An orange phosphorescent OLED was fabricated by employing the same exciplex system as the co-host and PO-01 as the phosphorescence emitter. The device shows a high maximum current efficiency (CE) of 61.15 cd/A, and the roll-off of just 0.13% from the maximum CE to the CE at 1000 cd/m2. Such high device efficiency and ultra-low roll-off in the orange PHOLEDs is attributed to the efficient Förster energy transfer processes and the well balanced charge-transporting abilities.