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The doping of transition metal ions in the up‐conversion (UC) luminescent material doped with Yb3+/Ln3+ is a facile way to increase their UC luminescence intensities and alter their colors. In this study, La2MgTiO6:Yb3+/Mn4+/Ln3+ (Ln3+ = Er3+, Ho3+, and Tm3+) phosphors showing excellent luminescence properties were prepared by a solid‐state method. The sensitivity of the La2MgTiO6:Yb3+/Ln3+/Mn4+ phosphor was double that without Mn4+, because Mn4+ affects the UC emissions of Ln3+ via energy transfer between these ions. Moreover, Mn4+ also acts as a down‐conversion activator, which can combine with UC ions to achieve multi‐mode luminescence at different wavelengths. Under 980 nm excitation, these samples emit green light (from Er3+ and Ho3+) and blue light (from Tm3+). In contrast, under 365 nm excitation, they emit red light (from Mn4+). Further testing revealed that the La2MgTiO6:Yb3+/Mn4+/Ln3+ phosphors have potential applications in temperature sensing and anti‐counterfeiting. [ABSTRACT FROM AUTHOR]

Tailoring the local crystal environment around the activators is one of an important way to enhance the upconversion (UC) luminescence intensity. Herein, we substitute the Y3+ lattice with La3+ ion gradually in Y2Ti2O7:Yb3+, Er3+ phosphor and investigate the effect of La3+ concentration on the UC luminescent properties as well as the temperature sensing behaviors. During the phase transformation process from cubic Y2Ti2O7 to monoclinic La2Ti2O7, the La3+ ions also play an important role on the adjustment of size and morphology of particles. Furthermore, the cooperation of La3+ ion is in favor of the crystal growth toward the easy growth directions. The UC luminescence intensities can be enhanced efficiently with the increasing of La3+ concentration. The sensitivity for temperature sensing can be improved by the increasing of La3+ concentration in the Y2Ti2O7 and La2Ti2O7 two‐phase coexistence system and the maximum SA is 45.3 × 10−4 K−1 at 410K when the La3+ concentration is 80%. The maximum SA and corresponding temperature can be adjusted by controlling the La3+ concentration, which means that (Y0.94‐xLax)2Ti2O7: Er3+/Yb3+ phosphors may be applicable to different working environment. [ABSTRACT FROM AUTHOR]

The doping of transition metal ions in the up‐conversion (UC) luminescent material doped with Yb3+/Ln3+ is a facile way to increase their UC luminescence intensities and alter their colors. In this study, La2MgTiO6:Yb3+/Mn4+/Ln3+ (Ln3+ = Er3+, Ho3+, and Tm3+) phosphors showing excellent luminescence properties were prepared by a solid‐state method. The sensitivity of the La2MgTiO6:Yb3+/Ln3+/Mn4+ phosphor was double that without Mn4+, because Mn4+ affects the UC emissions of Ln3+ via energy transfer between these ions. Moreover, Mn4+ also acts as a down‐conversion activator, which can combine with UC ions to achieve multi‐mode luminescence at different wavelengths. Under 980 nm excitation, these samples emit green light (from Er3+ and Ho3+) and blue light (from Tm3+). In contrast, under 365 nm excitation, they emit red light (from Mn4+). Further testing revealed that the La2MgTiO6:Yb3+/Mn4+/Ln3+ phosphors have potential applications in temperature sensing and anti‐counterfeiting. [ABSTRACT FROM AUTHOR]