Synthesis of Yb3+/Tm3+co-doped MF2 (M=Ca,Sr,Ba) nanocrystals with blue up-converted fluorescence

A series of MF(2):Yb(3+)/Tm(3+)(M=Ca, Sr, Ba) upconverted nanocrystals were synthesized by hydrothermal method. Polyvinylpyrrolidone(PVP) is an surfactant which can render the nanocrystals dispersible in water and ethanol. Upconverted emission was also detected in the red and NIR regions of the spectrum and assigned to the (1)G(4)-(3)F(4) (centered at 650 nm) and (3)H(4)-(3)H(6) (centered at 800 nm) transitions, respectively. In addition, MF(2):Yb(3+)/Tm(3+) NCs show bright blue upconverted emission under the 980 nm excitation. As-synthesized MF(2):Yb(3+)/Tm(3+) luminescent NCs might find some potential applications in areas of photoluminescence and displays.