Highly efficient nondoped green organic light-emitting devices based on a substituted triphenylpyridine derivative

Highly efficient nondoped green organic light-emitting devices based on a triphenylpyridine derivative, 4-[4-(dimethylamino)phenyl]-2,6-diphenylnicotinonitrile (NPDPN), were fabricated and characterized. The double-organic-layer device with a structure of ITO/alpha-napthylphenylbiphenyl diamine /NPDPN/LiF/Al, in which NPDPN was used as both the emitter and the electron transporter, exhibits a green emission with Commission Internationale de L'Eclairage (CIE) coordinates of (0.23,0.52) and a power efficiency of 5.5 lm/W. The result is much better than that of similarly structured device based on tris(8-hydroxyquinoline)aluminum. Furthermore, a high current efficiency of 8.4 cd/A was achieved with an optimized device configuration. c 2009 American Institute of Physics. [doi:10.1063/1.3242000]