Upconversion luminescence and Visible-Infrared Properties of β-NaLuF₄:Er³⁺ Microcrystals Synthesized by the Surfactant-Assisted Hydrothermal Method

Figure 1

XRD patterns of the as-synthesized products obtained in the presence of different surfactants (EDTA: S1 to S3, PVP: S4 to S6, and Ct³⁻: S7 to S9). The standard pattern of hexagonal NaLuF₄ (JCPDS card 27-0726) and orthorhombic LuF₃ (JCPDS card 17-0796) is also presented for comparison.

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