1,720,997 research outputs found
Effect of precursors on the morphology of lithium aluminate prepared by hydrothermal treatment
No full textHydrothermal treatment method was proposed to prepare pure LiAlO2 with fibrous crystal morphology and the effect of precursors on the morphology of lithium aluminate was investigated. Lithium butoxide-aluminum butoxide system gave mostly rod-like beta-LiAlO2 crystal. As the length of alkoxy group decreases, the fraction of plate shape crystals was increased and boehmite was dominant crystal phase. Needle-shape beta-LiAlO2 was produced from lithium nitrate-aluminum butoxide-sodium hydroxide system with the mole ratio of 6 : 1 : 3, respectively. beta-LiAlO2 prepared by hydrothermal treatment was transformed to gamma-LiAlO2 at 750-850 degrees C. The specific surface area of gamma-LiAlO2 powders was above 10 m(2)/g. (C) 2000 Kluwer Academic Publishers
The formation of phase pure lithium aluminate from the bulky lithium and aluminum alkoxides
No full textLow degradation and high annealing effects of amorphous silicon multilayer processed through alternate hydrogen dilution
No full textFabrication of protocrystalline silicon multilayer/protocrystalline silicon multilayer tandem solar cell for low degradation (Submitted)
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Characterization of the protocrystalline silicon multilayer
No full textThe protocrystalline silicon (pc-Si:H) multilayer solar cell is very promising owing to its fast stabilization with low degradation against light irradiation. However, the pc-Si:H multilayers have not extensively been investigated in detail on its material characteristics yet. We present the material characteristics of pc-Si:H multilayers using a transmission electron microscopy (TEM), Fourier transform infra (FTIR) spectroscopy, Raman spectroscopy, constant photocurrent method (CPM) and quantum efficiency (QE) measurement. A TEM micrograph shows that a pc-Si:H multilayer has a repeatedly layered structure consisting of low hydrogen-diluted and highly hydrogen-diluted sublayers. FTIR spectra depict the strong vibration mode at 2090 cm(-1) which is attributed to hydrogen-rich amorphous silicon (a-Si:H) regions of highly hydrogen-diluted sublayers. Based on these results, excellent light-soaking behavior of the pcSi:H multilayers is primarily due to the repeatedly layered structure that improves a structural order in the material. (c) 2006 Elsevier B.V. All rights reserved
Preparation of lithium aluminate via polymeric precursor routes
No full textGamma lithium aluminate is a potential candidate for tritium breeding material. Various preparation routes have been proposed including solid state reaction methods and wet chemical methods such as sol-gel process. But it is still needed to develop reliable and economic preparation methods that can be used for large production. In this paper, we examined three polymeric precursor methods - amorphous citrate process, Pechini process, and polyvinyl alcohol-assisted process - by studying thermal behavior of the precursor powders by X-ray diffractometry, differential thermal analysis, Infrared spectrometry, and BET surface area analysis. All these three processes produced phase pure gamma lithium aluminate powders at a relatively low temperature. The phase purity and processing temperature were comparable to the alkoxide derived sol-gel method and yet these polymeric precursor methods did not require high quality starting materials such as alkoxides. (C) 1998 Elsevier Science B.V. All rights reserved
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