Uniform Spheres of α-NaYF4:RE3+ (RE=Eu, Tb, Ce, Er, and Tm): Template-Free Synthesis, Multi-Color Photoluminescence, and Their Application in Cellular Imaging

Xiaofeng Fan, Laiqin Gu, Yiling Hu, Qi Zhu
2020 Crystals  
Uniformly dispersed luminescent probes with a high brightness and high resolution are desired in bio imaging fields. Here, ~100 nm sized and well-dispersed spheres of RE3+ doped α-NaYF4 (rare earth (RE) = Eu, Tb, Ce, Er, and Tm) have been facile synthesized through hydrothermal processing in the absence of a template, followed by a proper annealing. The processing window of the cubic structured spheres is wide, because the hydrothermal products are independent of the processing conditions,
more » ... ding reaction time and temperature. The original morphology and crystal structure can be well retained with a calcination temperature up to 600 °C. However, calcination gives rise to a reduction of particle sizes, as a result of the crystallite growth and densification. Under ultraviolet radiation, α-NaYF4:RE3+ spheres show characteristic f-f emissions of RE3+ (RE = Eu, Tb, Ce, Er, and Tm), and exhibit orange red, green, ultraviolet (UV), blue green, and blue emissions, respectively. Mainly because of the near-infrared emission at ~697 nm (5D0→7F4 transitions of Eu3+), the successful imaging of macrophages was achieved by NH2-NaYF4:Eu3+ probes, indicating their excellent imaging capacity for cells in vitro.
doi:10.3390/cryst10020119 fatcat:r22iz5djwbd3jjlwou3biq2kjy