期刊

CrystEngComm

标题

Salt-assisted rapid transformation of NaYF4:Yb3+,Er3+ nanocrystals from cubic to hexagonal

作者

Bangda Yin, Wenli Zhou, Qian Long, Chengzhi Li, Youyu Zhang and Shouzhuo Yao

摘要

High-quality hexagonal upconversion nanocrystals of β-NaYF4:Yb3+,Er3+ were prepared through a one-pot mild solvothermal synthesis. The crystal structure of NaYF4:Yb3+,Er3+ can rapidly transform from cubic (α-) to hexagonal (β-)phase in the presence of salts, such as sodium hydrogen phosphate (Na2HPO4). It was found that the size and structure of as-prepared NaYF4:Yb3+,Er3+ can be controlled by changing the molar ratio of phosphate to Ln3+(Ln3+ represents the total amount of Y3+ and the doped rare earth elements such as Yb3+, Er3+). A possible formation mechanism was proposed on the basis of XRD analyses and TEM observations of the products under different reaction conditions. The upconversion fluorescence at 550 nm of β-NaYF4:Yb3+,Er3+ nanocrystals with hexagonal structure and narrow size distribution was enhanced up to 22.5-fold compared to the cubic nanocrystals (α-NaYF4:Yb3+,Er3+). This study is also expected to provide a new synthetic strategy for the exploration of other complexes with controllable structures and optical properties.

原文链接

http://pubs.rsc.org/en/content/articlelanding/2014/ce/c4ce00650j