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キーワード:
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要旨:
The origin of the narrow particle size distributions obtained in the oleic acid-based synthesis of hexagonal phase β-NaREF4 nanocrystals (RE = Sm, Eu, Gd, Tb) has been investigated. Compared to the standard synthesis, the growth conditions were simplified by using small purified particles of either α-NaREF4 (cubic phase) or β-NaREF4 (hexagonal phase) as single-source precursors, thereby avoiding the complications arising from the simultaneous presence of molecular educts and intermediately formed small particles. The study shows that α-phase as well as β-phase particles grow by Ostwald-ripening but narrow particle size distributions of the β-NaREF4 product particles are only obtained when α-phase precursor particles are employed. Since the small particles are also formed as intermediate products in the standard synthesis of β-NaSmF4, β-NaEuF4, β-NaGdF4 and β-NaTbF4 particles, their crystal phase is an important parameter to obtain a narrow size distribution in these systems.
