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

Abstract

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 ²E_g → ⁴A_2g 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.