Red, green, blue and bright white upconversion luminescence of CaTiO3: Er3+/Tm3+/Yb3+ nanocrystals

Under laser excitation of 976 nm, the green and red UC emissions of CaTiO3: Er3+ nanocrystals were consistent with 2H11/2, 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2 transition of Er3+, respectively. The green and red UC luminescence of CaTiO3: Er3+/Yb3+ nanocrystals were significantly stronger than the counterpart of CaTiO3: Er3+ nanocrystals, which was resulted from energy transfer between Yb3+ and Er3+. The blue and red UC emissions of CaTiO3: Tm3+/Yb3+ nanocrystals near 480 and 650 nm were observed due to the 1G4 → 3H6 and 1G4→3F4 transition of Tm3+, respectively. The overall and relative UC luminescence intensities of Er3+/Tm3+/Yb3+ tridoped CaTiO3 nanocrystals were found to be depended highly on the concentration of Yb3+ and Tm3+, for which the involved mechanisms were demonstrated. By adjusting the concentration of Yb3+ and Tm3+, CaTiO3: Er3+/Tm3+/Yb3+ nanocrystals with the CIE coordinates close to (0.33, 0.33) were obtained.

CIE x–y chromaticity diagram displaying the chromaticity coordinate of the UC fluorescence from the CaTiO3: 0.5%Er3+/0.7%Tm3+/7%Yb3+ nanocrystals.Figure optionsDownload as PowerPoint slideHighlights
► Rare-earth doped CaTiO3 nanocrystals were synthesized.
► Multicolor upconversion luminescence was realized.
► Yb3+ and Tm3+ contents influence UC luminescence.
► White light was observed in CaTiO3: 0.5%Er3+/0.7%Tm3+/7%Yb3+ nanocrystals.