Temperature and Exciton Concentration Induced Excimer Emission of 4,4'-Bis(4''-Triphenylsilyl) Phenyl-1,1'-Binaphthalene and Application for Sunlight-Like White Organic Light-Emitting Diodes.

This paper demonstrates the influence of temperature, exciton concentration, and electron transportation layers on the excimer emission of a novel deep-blue material: 4,4'-bis(4''-triphenylsilyl) phenyl-1,1'-binaphthalene (SiBN), by studying the photoluminescence and electroluminescence spectra of SiBN-based film. We have further developed sunlight-like and warm-light white organic light-emitting diodes (WOLEDs) with high efficiency and wide-range spectra, using SiBN and bis(2-phenylbenzothiozolato-N,C2')iridium(acetylacetonate) (bt2Ir(acac)) as the blue excimer and yellow materials, respectively. The resulting device exhibited an excellent spectra overlap ratio of 82.9 % with sunlight, while the device peak current efficiency, external quantum efficiency, and power efficiency were 18.5 cd/A, 6.34 %, and 11.68 lm/W, respectively, for sunlight-like WOLEDs.

Electroluminescence in ruthenium(II) complexes.

We have investigated the electrochemical, spectroscopic, and electroluminescent properties of a family of diimine complexes of Ru featuring various aliphatic side chains as well as a more extended pi-conjugated system. The performance of solid-state electroluminescent devices fabricated from these complexes using indium tin oxide (ITO) and gold contacts appears to be dominated by ionic space charge effects. Their electroluminescence efficiency was limited by the photoluminescence efficiency of the Ru films and not by charge injection from the contacts. The incorporation of di-tert-butyl side chains on the dipyridyl ligand was found to be the most beneficial substitution in terms of reducing self-quenching of luminescence.