Delayed Fluorescence of A Dinuclear Copper(I) Complex

A highly emissive bis(phosphine)diarylamido dinuclear copper(I) complex (quantum yield = 57%) was shown to exhibit E-type delayed fluorescence by variable temp. emission spectroscopy and photoluminescence decay measurement of doped vapor-deposited films. The lowest energy singlet and triplet excited states were assigned as charge transfer states on the basis of theor. calcns. and the small obsd. S_1-T_1 energy gap. Vapor deposited OLEDs doped with the complex in the emissive layer gave a max. external quantum efficiency of 16.1%, demonstrating that triplet excitons can be harvested very efficiently through the delayed fluorescence channel. The function of the emissive dopant in OLEDs was further probed by several phys. methods, including elec. detected EPR, cyclic voltammetry, and photoluminescence in the presence of applied current. Work carried out at Eastman Kodak Company, Rochester, NY 14650, was done prior to Dec., 2009.