The Dynamics of Nanoparticle Growth and Phase Change During Synthesis of β-NaYF4
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- 作者：Paul B. May ; John D. Suter II ; P. Stanley May ; Mary T. Berry
- 刊名：Journal of Physical Chemistry C
- 出版年：2016
- 出版时间：May 5, 2016
- 年：2016
- 卷：120
- 期：17
- 页码：9482-9489
- 全文大小：476K
- 年卷期：0
- ISSN：1932-7455
文摘
We implement a model for nanocrystal growth and crystallographic phase transition during the synthesis of β-NaYF4. In this model, the size of the α-phase nanoparticles, formed during the heating of the precursor materials, grows slightly in mean diameter and broadens in distribution width until some particles reach a size at which the β phase is thermodynamically favored. Individual particles crossing this threshold convert to the β phase, and then, being less soluble than the α phase, grow at the expense of dissolving α-phase particles. Implementing a straightforward kinetic formalism for individual particle growth and a variable phase definition depending on particle size, the model reproduces, in a quantitative fashion, the experimentally observed growth dynamics of β- NaYF4:Yb,Er. This work supports a hypothesis that the β-particle seeds arise from a phase transition in individual α-phase particles. The model also suggests that the great variability observed in the duration of the stage during which the α particle ripen, before β particles begin to appear, may be attributed to rather small differences in the size distribution of the α particles formed during the heating of precursor material.