Fiber temperature sensor based on dual-wavelength emitting Mg0.388Al2.408O4: Mn2+/Mn4+ phosphors for real-time temperature monitoring

Single doped Mg 0.388 Al 2 O 3.408 O 4 phosphor was prepared and multivalent Mn ion (Mn 2+ and Mn 4+ ) emission was achieved in a single host. The structure, morphology, and luminescence characteristics of Mn ions in Mg 0.388 Al 2 O 3.408 O 4 were discussed in detail, especially the temperature dependent emission characteristics of Mn ions. Based on the fluorescence intensity ratio (FIR) of Mn 2+ versus Mn 4+ and the decay lifetime of Mn 4+ emission as the temperature readout, a dual-mode optical temperature-sensing mechanism was proposed and studied in the temperature range of 293–473 K. The maximum relative sensitivities ( S r ) are derived as 2.83 % K −1 (at 373 K based on FIR) and 3.40 % K −1 (at 473 K based on decay lifetime), respectively. The temperature sensing characteristics of Mg 0.388 Al 2.408 O 4 : Mn 2+ /Mn 4+ powders in a full fiber system were studied, which can provide thermal-sensitive emissions at dual-wavelengths for stable ratiometric temperature sensing with good precision and repeatability. The constructed all fiber temperature sensing system has been applied in the on-line monitoring of CPU temperature.