A novel yellow-emitting material, 5,5′′-bis{4-[bis(4-methylphenyl)amino] phenyl}-2,2′:5′,2′′-terthiophene, for organic electroluminescent devices

A novel amorphous molecular material, 5,5^′′-bis{4-[bis(4-methylphenyl)amino]phenyl}2,2^′:5^′,2^′′-terthiophene (BMA-3T), has been found to function as a yellow-emitting material in organic electroluminescent (EL) devices. Both the single layer EL device using BMA-3T alone and the double layer EL device consisting of an emitting layer of BMA-3T and an electron-transport layer of tris(8-quinolinolato)aluminum sandwiched between indium-tin-oxide (ITO) and an alloy of magnesium and silver (∼10:1) electrodes emitted a bright yellow light resulting from BMA-3T. The double layer EL device showed much better performances than the single layer EL device, exhibiting a maximum luminance of ∼13 000 ${\mathrm{cd\hspace{0.17em}m}}^{\text{−2}}$ at a driving voltage of 18 V, and a luminous efficiency of 1.1 ${\mathrm{lm\hspace{0.17em}W}}^{\text{−1}}$ at a luminance of 300 ${\mathrm{cd\hspace{0.17em}m}}^{\text{−2}}.$