We have developed a nontoxic method of synthesizing blue-emitting ZnSeTe/ZnSe/ZnS quantum dots (QDs), which can be employed to realize QD-based electroluminescent displays. By introducing excessive metal halides without highly toxic hydrofluoric acid, we achieved a very high photoluminescence quantum yield reaching 94%. Furthermore, for the first time, air-stable ZnSeTe/ZnSe/ZnS QDs were demonstrated by employing simple surface ligand exchange performed both in solution and solid states. Various spectroscopic studies revealed that initial carboxylate ligands could be very effectively replaced by our simple ligand exchange at room temperature. In addition, we significantly broadened the spectral range of QDs by increasing the Te ratio of the core; therefore, green-and red-emitting ZnSeTe/ZnSe/ZnS QDs were demonstrated. The air-stable Zn-based QDs with full color emission developed in our study can be used as superior emitters in displays.

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Y2O3 particles of various sizes have been prepared by flame spray pyrolysis using water-in-oil emulsion precursor solutions. We found that by varying the emulsion droplet size, the particle size of the prepared Y2O3 powder can easily be varied from 30 to 700 nm. In conventional spray pyrolysis, each droplet generated by the atomizer is converted to one particle. Thus, particle size can only be controlled by varying the concentration of the precursor, which results in a decrease in the generation rate. As in conventional spray pyrolysis, the flame spray pyrolysis of the emulsions was found to result in the conversion of one emulsion droplet to one particle. Control of particle size was achieved by varying the emulsion droplet size, which results in no decrease in the particle generation rate.

The H2S tolerance and stability of a Sm0.2Ce0.8O2-δ coating on the Ni/YSZ anode pore wall surface was investigated. The sulfur poisoning mechanisms were studied for various H2S concentrations (0-100 ppm) and temperatures (600°C and 700°C) under both open circuit voltage (OCV) and current-loading conditions. For the unmodified Ni/YSZ anode under current-loading conditions, the cell performance decreased significantly with the introduction of H2S, as the sulfur strongly adsorbed at the electrochemical reaction sites (ERSs). For the SDC-modified Ni/YSZ anode under the OCV conditions, the governing mechanism of the H2S poisoning was the formation of Ce2O2S with low oxygen ion conductivities, making the oxygen ion path disconnected. For the SDC-modified anode under current-loading conditions, the mixed ionic and electronic conductivity (MIEC) of the SDC allowed the electrochemical reactions to occur mainly at the SDC/fuel interface (2PB). With these conditions, the adsorbed sulfur was easily removed by the electrochemical oxidation. The decrease in the sulfur poisoning effect resulted in stable cell performances at 500 ppm of H2S over 800 h.