Journal of the American Chemical Society, Vol.120, No.46, 12100-12107, 1998
Solid-state light-emitting devices based on the trischelated ruthenium(II) complex. 1. Thin film blends with poly(ethylene oxide)
Thin-film solid-state light-emitting devices have been fabricated by using blends of a trischelated complex of ruthenium(II) with 4,7-diphenyl-1,10-phenanthroline disulfonate ligands and lithium triflate complexed poly(ethylene oxide). Charge injection occurs via an electrochemical redox mechanism and the mechanism of light production is similar to electrogenerated chemiluminescence. Orange-red light is emitted with a turn-on voltage of 2.5-3.0 V. At 6 V, devices reach luminance levels of about 100 cd/m(2) with an external quantum efficiency of 0.02% photons/electron. The admired PEO acts both as a film processing aid, giving uniform, homogeneous, and reproducible devices, and as a polymer electrolyte for ruthenium complex and counterion diffusion. Devices reach about 50% of their maximum luminance within a few seconds, and reach maximum luminance in about a minute. This behavior can be realized without the need of elaborate charging schemes involving the use of elevated temperatures or solvent treatments that enhance ionic conductivity. Devices of this type can be fabricated via conventional processing routes and conditioned to high light ouput with a few simple voltage scans.
Keywords:ELECTROGENERATED CHEMI-LUMINESCENCE, NAFION-COATED ELECTRODES;CONCENTRATION GRADIENTS, REDOX POLYMER, CHEMILUMINESCENCE;EMISSION, ELECTROCHEMISTRY, PLATINUM, ACETONITRILE, VOLTAMMETRY