High Brightness and Efficiency Yellow-Emitting Organic Electroluminescent Device

Yellow-light-emitting organic electroluminescent device with multilayer thin-film structure, which shows high brightness and efficiency, is constructed. The hole-transport layer is an N,N'-bis(3-methyphenyl)-N,N'-diphenylbe-nzidine film. The electron-transport layer is an 8-(quinolinolate)-aluminum(A1q) film. The luminescent layer consists of a host material Alq and an emitting dopant 5,6,11,12-petraphenyInaphthacene. The doped device exhibited the maximum emission 40000cd/m² at 19V, and the maximum efficiency of 3.141m/W, which have been improved by about six and three times, respectively, in comparison with that in undoped device. For the unpackaged device, a luminance half-life on the order of about 230 h has been achieved with a constant current density of 15mA/cm², starting at 500cd/m² at the room temperature under ambient atmosphere.