Figure 5.

(a) UCL emission spectra of NaYF₄:5%Yb³⁺/30%Mn²⁺ nanoparticles with different synthesis temperatures (120 °C, 140 °C, 160 °C, 180 °C and 200 °C) and (b) log intensity versus synthesis temperature under 980 nm CW excitation. (c) UCL emission spectra of NaYF₄:5%Yb³⁺/x%Mn²⁺ (x% = 20, 30, 40, 50, 60 and 70%) nanoparticles and (d) log intensity versus Mn²⁺ concentration under 980 nm CW excitation. (e) UCL emission spectra of NaYF₄:40% Mn²⁺/x%Yb³⁺ (x% = 1, 5, 10, 20, 30 and 40%) nanoparticles and (f) log intensity versus Yb³⁺ concentration under 980 nm CW excitation. The pulse duration for the impact mode was 3 min, the power density of the 980 nm laser was 1 W/cm², and the spot width was 3 mm. 1000 µl of the solution was poured into the cuvette and the cuvette was placed inside the measuring device.