A new series of cationic blue-emitting, heteroleptic iridium(III)-based metal complexes were systematically synthesized using two 4,6-difluorophenylpyridine ligands as well as one methyl- or n-butyl-substituted bisimidazolium salt carbene-type ligand. In degassed CH(2)Cl(2), all complexes display highly efficient, blue phosphorescence (λ(max) ∼ 452 nm; emission quantum yield ∼ 0.30) at room temperature and also show blue emission in a thin film. The measured photophysical properties of the complexes have been rationalized with the help of quantum-chemical calculations. Because of the high solubility of the complexes, solution-processed devices, light-emitting electrochemical cells (LEECs), were made. The results showed that true blue emission and short turn-on time is achieved when an ionic conductor, tetrabutylammonium trifluoromethanesulfonate, was used as the matrix for the film containing the emitters. These iridium complexes and the described devices are the bluest materials ever reported and the first case of LEECs based on carbene ligands.

Methane clathrate formation on water films without previous hydrate formation history was studied. It was found that hydrates form in two layers, each with a clearly distinct morphology. As the clathrate aged, this difference in morphology tended to disappear. Higher driving forces produced smaller hydrate grains and smoother surfaces than lower driving forces within the water film. The converse was true for hydrate formed on the periphery. A third hydrate layer growing outside of the original water boundary was also observed. For the first time, it was shown that this growing front could induce nucleation by creating a "bridge" between segregated water droplets. Hydrate reformation was also studied and it was found that it proceeded in a manner different than that of a system without previous clathrate formation history. For reformation, nucleation occurred within the film and a circular hydrate front(s) advanced toward the periphery of the water film with uniform morphology.

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