A high sensitivity dual-mode optical thermometry based on charge compensation in ZnTiO₃:M (M = Eu³⁺, Mn⁴⁺) hexagonal...

Optical thermometer based on dual-mode fluorescence intensity ratiometric thermometry has been attracted more attention due to its higher sensitivity. In order to obtain optical thermal probe with high sensitivity, ZnTiO₃ hexagonal prisms with hexagonal perovskite structure were fabricated by using self-assembly method, and Al³⁺ ions were introduced into the crystal lattices of ZnTiO₃ doped with Eu³⁺/Mn⁴⁺ to improve the optical properties. The emission intensity assigned to Eu³⁺ was enhanced about twice with the charge compensation of Al³⁺ between Eu³⁺ and Ti³⁺. While the luminescence ratio between the thermal coupled level of Eu³⁺ revealed poor temperature dependence property. The emission assigned to ²E_g→⁴A_2g (713 nm) transition of Mn⁴⁺ revealed an huge thermal quenching. Using the luminescence ratio between ⁵D₀→⁷F₂ (⁵D₀→⁷F₁) transition of Eu³⁺ to ²E_g→⁴A_2g of Mn⁴⁺, the higher relative sensitivity of 2.7 %K^-1was obtained. The charge compensation of Al³⁺ improved the coordination and reduced the relative sensitivity, Sr =1.85 %K^-1. The results suggested the potential application in optical temperature probes for ZnTiO₃: Mn⁴⁺,Eu³⁺ phosphor.