Multifunctional optical thermometry based on La2MgSnO6:Mn4+, M (M=Bi3+, Sm3+) double perovskite phosphors

To develop novel luminescent materials for optical thermometry, a series of La2MgSnO6:Mn4+, M (M = Bi3+, Sm3+) phosphors were prepared by the solid-state method. Upon UV excitation, the La2MgSnO6: Mn4+ sample demonstrates strong red emission originating from the 2Eg -> 4A2g transition of Mn4+. By co-doping with Bi3+ or Sm3+, it becomes possible to achieve tunable emission in La2MgSnO6 phosphors. Due to the different thermal quenching behavior between the Mn4+ and Bi3+ or Sm3+, a high-sensitivity thermometric was developed using the fluorescence intensity ratio mode. The maximum sensitivity was obtained to 1.5 %K-1 at 473K. The emission spectra of La2MgSnO6: Mn4+, M (M = Bi3+, Sm3+) phosphor significantly coincide with the absorption spectra of plant pigments in the blue and red regions. These findings indicate that the as-prepared La2MgSnO6: Mn4+, M (M = Bi3+, Sm3+) phosphors are promising candidate materials for plant cultivation and high-temperature optical thermometry.