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

Figure 3

The TEM images, HRTEM images, and ED patterns of as-prepared β-NaLuF₄ microcrystals using different surfactants: (a) S3, (b) S6, (c) S8, and (d) S9.

(a)

(b)

(c)

(d)