Infrared-to-visible and infrared-to-violet upconversion fluorescence of rare earth doped LaF3 nanocrystals

This paper reports that hexagonal-phase LaFupconversion fluorescence,infrared-to-visible, infrared-to-violet, nanocrystalsProject supported by the NationalNatural Science Foundation ofChina (Grant Nos 10474096 and 50672030).3250F, 7855This paper reports that hexagonal-phase LaFupconversion fluorescence,infrared-to-visible, infrared-to-violet, nanocrystalsProject supported by the NationalNatural Science Foundation ofChina (Grant Nos 10474096 and 50672030).3250F, 7855This paper reports that hexagonal-phase LaFupconversion fluorescence,infrared-to-visible, infrared-to-violet, nanocrystalsProject supported by the NationalNatural Science Foundation ofChina (Grant Nos 10474096 and 50672030).3250F, 7855This paper reports that hexagonal-phase LaF$_{3}$:Yb$^{3 +}_{0.20}$, Er$^{3 + }_{0.02}$ and LaF$_{3}$:Yb$^{3 + }_{0.20}$,Tm$^{3 + }_{0.02}$ nanocrystals (NCs) were synthesized via ahydrothermal method. The transmission electron microscopy, selectedarea electron diffraction, powder x-ray diffraction, andthermogravimetric analysis are used to characterize the NCs. Under980 nm excitation, the Yb$^{3 + }$/Er$^{3 + }$ and Yb$^{3 +}$/Tm$^{3 + }$ codoped NCs colloidal solutions present bright greenand blue upconversion fluorescence, respectively. These NCs showefficient infrared-to-violet and infrared-to-visible upconversion.The upconversion fluorescence mechanisms of LaF$_{3}$:Yb$^{3 +}_{0.20}$, Er$^{3 + }_{0.02}$ and LaF$_{3}$:Yb$^{3 + }_{0.20}$,Tm$^{3 + }_{0.02}$ NCs are investigated with a 980-nm diode laser asexcitation source.