None-rare-earth Activated Ca14Al10Zn6O35:Bi3+,Mn4+ Phosphor Involving Dual Luminescent Centers for Temperature Sensing

We proposed a new strategy for utilizing rare-earth-free-activated self-referencing optical material with dual activators for temperature sensing, which was synthesized by conventional high-temperature solid-state method and was scarcely reported. Originating from the different thermal responses of Mn4+ and Bi3+ ions, a Mn4+/Bi3+-based dual-emitting fluorescence intensity ratio (FIR) as dual-modal temperature signal for temperature sensing has been corroborated as a promising temperature sensing method. Due to the outstanding thermal resistance of activator Mn4+ (anti-Stokes) benefiting from the unique 3d(n) electronic configurations and strong field strength of host, together with the energy transfer from Bi3+ to Mn4+ ions and excellent thermal quenching of Bi3+, this temperature-sensitive phosphor displayed both an extensive detection temperature region ranging from 303 to 563 K and excellent absolute and relative sensitivity of 0.0147 K-1 and 1.21% K-1 respectively, both of which are higher than some foregoing reported optical materials. Furthermore, two well-separated emission peaks at blue and red regions enabled an excellent signal discriminability and accurate temperature detection under the single-wavelength excitation of 340 nm. In addition, freedom from rare-earth ions contributed its possibility to be mass-produced for meeting the needs of economic rationality, nontoxic and convenient synthesis. It is anticipated that this preliminary study would arouse peoples' attention on exploring more novel dual activator-based optical thermometric materials in absence of rare-earth ions.