Benzo[d]imidazole-functionalized triazatruxenes as the emitting materials for solution-processed non-doped OLEDs

Two benzo[d]imidazole/triazatruxene hybrid compounds, 5,10,15-tributyl-2,7,12-tris(4-(1-phenyl-1H-benzo[d]imidazole-2-yl)phenyl)-10,15-dihydro-5H-diindolo[3, 2-a:3',2'-c]carbazole (2,7,12-TBI-TAT) and 5,10,15-tributyl-3,8,13-tris(4-(1-phenyl-1H-benzo[d]imidazole-2-yl)phenyl)-10,15-dihydro-5H-diindolo[3,2-a:3',2'-c] carbazole (3,8,13-TBI-TAT), were synthesized by the introduction of three benzo[d]imidazole (BI) moieties at 2-, 7-, 12-positions and 3-, 8-, 13-positions of the alkylated triazatruxene (TAT) core, respectively. Their thermal stabilities, photophysical and electrochemical properties were systematically investigated. These hybrid compounds exhibited good solubility as well as excellent thermal stability. Besides, the solution-processed doped and nondoped OLEDs based on the compounds were fabricated, in which the non-doped device fabricated from 2,7,12-TBI-TAT exhibited the best electroluminescence performance with a maximum brightness of 10075 cd/m(2), a maximum current efficiency of 5.35 cd/A and a maximum external quantum efficiency (EQE) of 2.25%.

Automated summary

Two benzo[d]imidazole/triazatruxene hybrid compounds were synthesized and their thermal stabilities, photophysical, and electrochemical properties were investigated. These compounds showed good solubility and thermal stability, with the non-doped OLED device based on 2,7,12-TBI-TAT displaying the best electroluminescence performance.