Highly Efficient Green Organic Light-Emitting Diodes Containing Luminescent Three-Coordinate Copper(I) Complexes

A series of highly emissive three-coordinate copper(I) complexes, (dtpb)Cu(I)X [X = Cl (1), Br (2), I (3); dtpb = 1,2-bis(o-ditolylphosphino)benzene], were synthesized and investigated in prototype organic light-emitting diodes (OLEDs). 1-3 showed excellent photoluminescent performance in both degassed dichloromethane solutions [quantum yield (Phi) = 0.43-0.60; lifetime (tau) = 4.9-6.5 mu s] and amorphous films (Phi = 0.57-0.71; tau = 3.2-6.1 mu s). Conventional OLEDs containing 2 in the emitting layer exhibited bright green luminescence with a current efficiency of 65.3 cd/A and a maximum external quantum efficiency of 21.3%.