Organic light-emitting diodes using novel metal-chelate complexes

Electroluminescent (EL) properties of novel metal-chelate complexes have be en investigated in the organic light-emitting diodes (OLEDs) comprised of t he hole transport layer (HTL) and emitting layer (EML). The metal-chelate c omplexes have either polycyclic aromatic or fused ring ligands, which coord inate to zinc or aluminum. Various EL emission colors over the range of blu e to yellow were obtained. The OLEDs using the complexes with polycyclic ar omatic ligands showed desirable blue emission with a quantum efficiency of 1.5-1.7% at a luminance of 300 cd/m(2) and CIE color coordinates of around (0.17, 0.16). By perylene-doping into the blue-emitting complex, the improv ement of EL efficiency was observed. On the other hand, the complex with fu sed ring ligands gave a quantum efficiency of 0.8% at yellow emission. (C) 2000 Elsevier Science S.A. All rights reserved.