Research Article
Morphology Manipulation and Upconversion Luminescence Enhancement of β-NaLuF4: Er3+ Hexagonal Microtubes via Sr2+ Doping
Figure 7
Log-log of the UC emission intensity against laser excitation power for NaLuF4:6%Er3+, % Sr2+ samples with , 5, 10, 18, 25, 30 (color figure online).
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