Figure 1
From: Morphological evolution of upconversion nanoparticles and their biomedical signal generation
SEM images of the NaYF4:Yb3+/Er3+ UCNP synthesized using different HR temperatures and times. (a) 2, 8, 10, 24 h at 180 °C. (b) 2, 7, 8, 24 h at 190 °C. (c) 2, 3, 5, 24 h at 200 °C. (d) 2, 3, 5, 24 h at 210 °C.
